Preparation of Very Thin Zinc Oxide Films by Liquid Deposition Process: Review of Key Processing Parameters

We used sol-gel and spin-coating in the original configuration of a liquid deposition process to synthesize particularly thin ZnO films (<100 nm) with nano-granular morphology, high grain orientation and variable optical properties. The concentration of the zinc salt, the concentration of the chelating agent, the nature of the solvent and the substrate material have been identified as key parameters that determine the microstructure of the deposited layer and thus its final properties. The thorough and practical examination of the effects of the synthesis parameters evidenced a three-step growth mechanism for these ZnO thin films: (i) a reaction of precursors, (ii) a formation of nuclei, and (iii) a coalescence of nanoparticles under thermal annealing. The growth of these very thin films is thus conditioned by the interaction between the liquid phase and the substrate especially during the initial steps of the spin coating process. Such thin ZnO films with such nano-granular morphology may be of great interest in various applications, especially those requiring a large active surface area.

Effect of Cooling Rate on the Microstructure Evolution and Mechanical Properties of Iron-Rich Al–Si Alloy

The mechanical properties of iron-rich Al–Si alloy is limited by the existence of plenty of the iron-rich phase (β-Al5FeSi), whose unfavorable morphology not only splits the matrix but also causes both stress concentration and interface mismatch with the Al matrix. The effect of the cooling rate on the tensile properties of Fe-rich Al–Si alloy was studied by the melt spinning method at different rotating speeds. At the traditional casting cooling rate of ~10 K/s, the size of the needle-like β-Al5FeSi phase is about 80 μm. In contrast, the size of the β-Al5FeSi phase is reduced to 500 nm and the morphology changes to a granular morphology with the high cooling rate of ~104 K/s. With the increase of the cooling rate, the morphology of the β-Al5FeSi phase is optimized, meanwhile the tensile properties of Fe-rich Al–Si alloy are greatly improved. The improved tensile properties of the Fe-rich Al-Si alloy is attributed to the combination of Fe-rich reinforced particles and the granular silicon phase provided by the high cooling rate of the melt spinning method.

CFD-DEM Modeling of Dense Sub-Aerial and Submerged Granular Collapses

Sub-aerial (dry) and submerged dense granular collapses are studied by means of a three-phase unresolved computational fluid dynamics-discrete element method (CFD-DEM) numerical model. Physical experiments are also performed to provide data for validation and further analysis. Validations show good compatibility between the numerical and experimental results. Collapse mechanism as well as post-collapse morphological parameters, such as granular surface profile and runout distance, are analyzed. The spatiotemporal variation of solid volume fraction is also investigated. The effect granular column aspect ratio is studied and found to be a key factor in granular morphology for both submerged and dry conditions. The volume fraction analysis evolution shows an expansion and re-compaction trend, correlated with the granular movement.

Yams.

This chapter discusses the extraction of starch from different yam (Dioscorea) species. The physiochemical (biochemical property, amylose and amylopectin content), structural (granular morphology, X-ray diffraction pattern, starch crystallinity, and amylose and amylopectin structure), functional (swelling pattern, solubility, viscosity, rheological properties and retrogradation) and thermal properties of yam starches and their digestibility are described.

Other starches.

This chapter discusses the extraction, physiochemical (chemical composition, amylose and amylopectin content), structural (granular morphology, X-ray diffraction pattern, starch crystallinity, and amylose and amylopectin structure), functional (swelling pattern, solubility, viscosity, rheological properties and retrogradation) and thermal properties, and digestibility of starches from minor tuber crops (e.g., arrowroot, Curcuma spp., Canna edulis [C. indica], Chinese water chestnut [Eleocharis dulcis], chayote [Sechium edule], Pachyrhizus ahipa, Oxalis tuberosa, Arracacia xanthorrhiza, Lilium spp.).

Aroids.

This book chapter outlines the extraction and purification, physiochemical composition (i.e. biochemical content, amylose and amylopectin content), structural properties (i.e. granular morphology, XRD and starch crystallinity, amylose and amylopectin structure), functional properties (i.e. swelling and solubility, viscosity, rheological properties, retrogradation), thermal properties (i.e. DSC, digestibility) of aroids.