Glass, heterogeneous

Fig. 4.4 Dependences of the normalized shear moduli of epoxy resin filled with glass heterogeneities on the volume fraction of filler f. curves 1 and 5 are for particle aspect ratio...

Orrit M (2013) Towards a molecular view of glass heterogeneity. Angew Chem Int Ed 52 (1) 163-166... 

Supported aqueous phase (SAP) catalysts (16) employ an aqueous film of TPPTS or similar ligand, deposited on a soHd support, eg, controlled pore glass. Whereas these supported catalysts overcome some of the principal limitations experienced using heterogeneous catalysts, including rhodium leaching and rapid catalyst deactivation, SAP catalysts have not found commercial appHcation as of this writing. 

Other important uses of stannic oxide are as a putty powder for polishing marble, granite, glass, and plastic lenses and as a catalyst. The most widely used heterogeneous tin catalysts are those based on binary oxide systems with stannic oxide for use in organic oxidation reactions. The tin—antimony oxide system is particularly selective in the oxidation and ammoxidation of propylene to acrolein, acryHc acid, and acrylonitrile. Research has been conducted for many years on the catalytic properties of stannic oxide and its effectiveness in catalyzing the oxidation of carbon monoxide at below 150°C has been described (25). 

Polyacetylenes. The first report of the synthesis of a strong, flexible, free-standing film of the simplest conjugated polymer, polyacetylene [26571-64-2] (CH), was made in 1974 (16). The process, known as the Shirakawa technique, involves polymerization of acetylene on a thin-film coating of a heterogeneous Ziegler-Natta initiator system in a glass reactor, as shown in equation 1. 

Membrane Tyjie.s A detailed taxonornv oF membranes is bevond the scope oF this handbook. Membranes rnav be made From physical solids (metal, ceramic, etc.), homogeneous Films (polvmer, metal, etc.), heterogeneous solids (polvmer mixes, mixed glasses, etc.), solutions (iisiiallv polvmer), a.svmrnetric structures, and liquids. 

Catalytic A catalytic-membrane reactor is a combination heterogeneous catalyst and permselective membrane that promotes a reaction, allowing one component to permeate. Many of the reactions studied involve H9. Membranes are metal (Pd, Ag), nonporous metal oxides, and porous structures of ceran iic and glass. Falconer, Noble, and Speriy [in Noble and Stern (eds.), op. cit., pp. 669-709] review status and potential developments. 

You can observe heterogeneous nucleation easily in carbonated drinks like "fizzy" lemonade. These contain carbon dioxide which is dissolved in the drink under pressure. When a new bottle is opened the pressure on the liquid immediately drops to that of the atmosphere. The liquid becomes supersaturated with gas, and a driving force exists for the gas to come out of solution in the form of bubbles. The materials used for lemonade bottles - glass or plastic - are poor catalysts for the heterogeneous nucleation of gas bubbles and are usually very clean, so you can swallow the drink before it loses its "fizz". But ordinary blackboard chalk (for example), is an excellent former of bubbles. If you drop such a nucleant into a newly opened bottle of carbonated beverage, spectacular heterogeneous nucleation ensues. Perhaps it is better put another way. Chalk makes lemonade fizz up. 

Dinelli, F, Buenviaje, C. and Ovemey, R.M., Glass transition measurements on heterogeneous surfaces. Thin Solid Films, 396(1-2), 138-144 (2001). 

As with organic solvents, proteins are not soluble in most of the ionic liquids when they are used as pure solvent. As a result, the enzyme is either applied in immobilized form, coupled to a support, or as a suspension in its native form. For production processes, the majority of enzymes are used as immobilized catalysts in order to facilitate handling and to improve their operational stability [24—26]. As support, either inorganic materials such as porous glass or different organic polymers are used [27]. These heterogeneous catalyst particles are subject to internal and external... 

The glass membrane of the electrodes discussed above may be replaced by other materials such as a single crystal or a disc pressed from finely divided crystalline material it may be advantageous to incorporate the crystalline material into an inert carrier such as a suitable polymer thus producing a heterogeneous-membrane electrode. 

Alloys can be classified as either homogeneous or heterogeneous. The former can be depicted as a solution with a single phase or single glass-transition temperature (7 ). A heterogeneous alloy has both continuous... 

Fig. 6. Side-arm tube of the apparatus for the determination of the coefficients of the heterogeneous recombination, y, of atomic gases previously dissociated in the rf discharge zone. The heterogeneous recombination proceeds on the inner glass walls of the horizontal side-arm tube and on a catalytically active cylindric sample of the metal investigated (Smith-Linnett method).

Inside ABCD, the crystalline solid is stable, above ABC the liquid, whilst to the right of CD the stable form is the amorphous glass. Roozeboom, however, holds a different opinion as to the latter part of the curve Heterogene Gleichge-u ichte, vol. I.). 

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