Solid packing properties

Chapter 1 is an introduction to crystal stractures and the iorric model. It introduces many of the crystal structures that appear in later chapters and discusses the concepts of iorric radii and lattice energies. Ideas such as close-packed structures and tetrahedral and octahedral holes are covered here these are used later to explain a number of solid state properties. 

If the catalyst deactivates rapidly or whenever good heat transfer properties are essential and where local hot spots cannot be accepted, the slurry reactor should also be considered. Finally, the slurry reactor can be an attractive alternative to multitube gas-solid packed-bed processes, particularly where large heat effects ask for thousands of thin tubes to control the reactor temperature in the packed beds. Also here, the much better heat transfer characteristics of slurries relative to gas-solid packed beds are deciding. 

An intriguing property of PFs is their ability to form liquid crystalline phases [38,39]. Besides the different mesophases which are classified as nematic, poly(9,9-dioctyl)fluorene (PFO) shows several solid-state packing properties and polymorphs. The pioneering work of Grell et al. showed how solvent swelling and thermal cycling could be used to control the solid-state packing in PFO thin films [38,40]. In addition, the different phases show remarkably diverse photophysical properties, which have tremendous... 

A suspension is a dispersion of solid particles in a liquid. A colloidal suspension is a sol. Colloidal properties become significant when the size of the parhcles is of the order of a few micrometer or less. In suspensions of large particles, for example, of some 10 pm or higher, hydrod5mamic interactions dominate the suspension flow properties emd particle packing behaviour. In colloidal suspensions interaction forces between the particles as well as hydro-dynamic interactions play a role in determining the flow and particle packing properties. 

Experience has shown structured fluids to be more difficult to manufacture, due to the complexity of their rheological profiles. In addition to elasticity, dilatancy, and rheopexy, certain structured fluid compositions may exhibit solid-like properties in the quiescent state and other flow anomalies under specific flow conditions. For emulsions and solid particulate dispersions, near the maximum packing volume fraction of the dispersed phase, for example, yield stresses may be excessive, severely limiting or prohibiting flow under gravity, demanding special consideration in nearly all unit operations. Such fluids pose problems in... 

The topochemical polymerization of monomers with conjugated triple bonds is an interesting example of the relationship between packing properties and reactivity in the solid state. For solid state polymer-izability the monomer molecules must be arranged in a herringbone-like structure according to Figure 1 so that only one nearest distance between the triple bonds of adjacent molecules of 3 to 4 A is affected. To... 

In many of these compounds, the one-dimensional solid state properties derive from interactions between planar molecular units which are stacked together to form columns or even metal atom chains along one direction in the solid. The tendency of planar molecules to stack in columns can be understood simply from the standpoint of packing eflS-ciency considerations although, in certain cases, specific bonding interactions are evidenced by unusually short intermolecular separations (6,... 

A foam is a dispersion of a gas in a liquid or a solid. The formation of foam relies on the surface activity of the surfactants, polymers, proteins, and colloidal particles to stabilize the interface. Thus, the foamability increases with increasing surfactant concentration up to critical micelle concentration because above critical micelle concentration, the unimer concentration in the bulk r ains nearly constant. The structure and molecular architecture of the foam is known to influence foam-ability and its stability. The packing properties at the interface are not excellent for very hydrophilic or very hydrophobic drug. The surfactant promoting a small spontaneous curvature at interface is ideal for foams. Nonionic surfactants are the most commonly used one. The main advantage with foams is its site-specific delivery and multiple dosing of the drug. ... 

We have expressed the molar viscous flux in terms of separate contribution from the pressure gradient, the fluid property (viscosity p), the solid property (dp) and the packing property K(e). There are different models in the literature about the functional form for K(e). Here we present a popular model credited to Blake. 

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