29 research outputs found
Physical Methods for the Preparation of Hybrid Nanocomposite Polymer Latex Particles
In this chapter, we will highlight conceptual physical approaches towards the fabrication of nanocomposite polymer latexes in which each individual latex particle contains one or more "hard" nanoparticles, such as clays, silicates, titanates, or other metal(oxides). By "physical approaches" we mean that the "hard" nanoparticles are added as pre-existing entities, and are not synthesized in situ as part of the nanocomposite polymer latex fabrication process. We will narrow our discussion to focus on physical methods that rely on the assembly of nanoparticles onto the latex particles after the latex particles have been formed, or its reciprocal analogue, the adhesion of polymer onto an inorganic nanoparticle. First, will discuss the phenomenon of heterocoagulation and its various driving forces, such as electrostatic interactions, the hydrophobic effect, and secondary molecular interactions. We will then address methods that involve assembly of nanoparticles onto or around the more liquid precursors (i.e., swollen/growing latex particles or monomer droplets). We will focus on the phenomenon of Pickering stabilization. We will then discuss features of particle interaction with soft interfaces, and see how the adhesion of particles onto emulsion droplets can be applied in suspension, miniemulsion, and emulsion polymerization. Finally, we will very briefly mention some interesting methods that make use of interface-driven templating for making well-defined assembled clusters and supracolloidal structures
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Differentiation of Serviceberry Habitats in the Wasatch Mountains of Utah
Utah serviceberry (Amelanchier utahensis Koehne) and its habitats were studied in the Wasatch Mountains of central Utah. Twenty-five populations were selected and sampled for various biotic and abiotic environmental variables. Regression, correlation, cluster, and discriminant analyses were used to analyze the data. Sites of northern exposure exhibited a more luxuriant vegetation than southern exposures. Although all the study sites contained Utah serviceberry as a dominant or subdominant plant, they can be classified into three major habitat types according to associated dominants and/or geographical location. These groups are serviceberry-dominated foothill knolls; oak-serviceberry-dominated northern exposures; and serviceberry-dominated southerly exposures. Analyses demonstrated overlap between the major selected habitat types. The most distinct habitat was the foothill knolls; the least distinct was the southern exposed serviceberry habitat. The serviceberry habitat on southerly exposures is environmentally intermediate between the foothill knolls and higher elevation northern exposed sites on which serviceberry shares dominance with oak. Discriminant analysis indicated that pH, slope, sand, soluble salts, and clay were the environmental factors most important in distinguishing between the major habitat types.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202