Heterogenous products

Two important browns, other than benzidine derivatives, are of azo chemical composition. Direct Brown 30 [6222-60-2] (82) (Cl 17630) is produced by coupling Primuline [30133-37-2] (Cl 49000) to N-phenylgamma acid under alkaline conditions. Direct Brown 44 [6252-62-6] (Cl 35005-35010) is produced by coupling two moles of sulfanilic acid to Bismark Brown [10114-58-6] (Basic Brown 1) (Cl 21000) forming a heterogeneous product with a significant component (83). 

Similar to other raw materials, e.g., metals, it is principally possible to vary the properties of macromolecular substances by mixing two or more different polymers. Though, one has to pay attention to the fact that in most cases phase-separated, i.e., heterogeneous products are obtained by mixing macromolecules. These polymer blends consist of a continuous phase (matrix) in which a discontinuous (dispersed) phase in the form of more or less regularly shaped particles is included. This phenomenon can be explained thermodynamically ... 

Hegg, D. A., Heterogeneous Production of Cloud Condensation Nuclei in the Marine Atmosphere, Geophys. Res. Lett., 17, 2165-2168 (1990). 

FIGURE 16.13 Comparison of observed O, concentration-time profiles (O) in two different evacuable chambers to predicted profiles if the heterogeneous production of HONO (reaction (14)) does not occur (curve A) and if reaction (14) with photoenhancement does occur (curve B). Results in (a) are results from the chamber of Akimoto el al. (1985) and those in (b) are from the evacuable chamber in Fig. 16.3 (adapted from Sakamaki and Akimoto, 1988). 

Commercial polyesters are heterogeneous products consisting of some... 

Combs (a) Uniform (fixed number of equally-spaced equal branches) (b) Randomly spaced (fixed number of equal branches) (c) Random lengths (fixed number of branches) (d) Heterogeneous (product of random coupling between equal branches and homogeneous backbone) (19.20.21.25.29) (29) (20) (19.29)... 

The net rate of production of gas-phase species by heterogeneous reaction participates in the boundary condition through the surface mass balance (Eq. 17.24). However, since the heterogeneous production rates of gas-phase species depends on the surface composition, the transient state of the surface composition must also be determined. As discussed in Section 11.10 the surface site fractions Z are found from the solution of... 

Ammann, M Kalberer, M, Jost, D.T., Tobler, L., Rdssler, E., Piguet, D., Gaggerler, H.W., and Balteispeiger, U. (1998) Heterogeneous production of nitrous acid on soot in polluted air masses. Nature 395,157-160. 

Characteristics of the Graft Polymerization Process. Under certain polymerization conditions such as when the vinyl chloride/polyethylene ratio is high, heterogeneous products are obtained in the sense that, beside the polyethylene grains gorged with PVC, independent suspension PVC particles are formed. Since the optimum conditions for production of PVC and graft copolymers are not necessarily identical, it is advantageous to avoid the formation of these independent PVC particles. 

Most of these polymers have multi-functional character, which results in cross-linked heterogeneous products. In contrast, monomethoxy polyethylene glycol (PEG) presents only one reactive terminal group per polymer chain. Once PEGy-lated with these compounds, the protein acquires a brush-like shape, with the hydrophilic PEG chains extended from the protein to the solvent. 

As well as differing between tumors of different types, angiogenic factor expression may vary between individual tumor cells within a tumor. This heterogeneous production of factors between subclones of tumor cells within a primary tumor is reflected by variations in factor production between primary tumors and their metastases [52], Indeed, inconsistent relationships between matched individual tumors and their metastatic deposits in their levels of vascularity and endothelial cell proliferation may indicate that angiogenic factor production by the metastasizing clone differs from that in the primary tumor [53],... 

Key to the success of this co-cyclotrimerization procedure is the selection of the appropriate monomers. A co-cyclotrimerization in which one monomer reacts much more rapidly than the other will result in a heterogeneous product as the monomer ratio changes. Moreover, if the mono-ethynyl capping agent reacts much more slowly than the multi-ethynyl monomer, gel formation can occur early in the reaction. Alternatively, if the mono-ethynyl material reacts much more rapidly, it can be exhausted early in the reaction, having produced a non-reactive trimer, and the multi-ethynyl monomers will gel later in the reaction. These problems can be avoided by using monomers of comparable reactivity or by adjusting the feed ratio to compensate for unequal reactivities. With either approach, it is necessary to determine the relative cyclotrimerization rates of each ethynyl monomer. In this paper, we report the initial results of our measurements of these rates. 

Although not included in this paper, a field experiment has been designed for the Kern River Unit located at the edge of the Kern River field, Kern County, California. The ideal emulsification properties of the crude oil have already been discussed in this paper. This field is an example of reservoir properties that should be considered ideal when selecting a reservoir for future testing of the process heterogeneous production zones, areas of low and high oil saturations, low salinity, low clay content, and crude oil that is easily emulsified. 

Co-precipitation. - The preparation of supported catalysts by the coprecipitation of metal ions with the support ions usually produces an intimate mixing of catalysts and support. An example of this technique is the coprecipitation of metal ions with aluminium ions to produce a precipitated alumina gel containing the metal hydroxide. This precipitate when calcined produces a refractory support with active component dispersed throughout the bulk as well as at the surface. However, in the preparation of multi-component catalysts, it is possible under improper conditions to obtain a heterogeneous product because of the different solubility products of the constituents. Care should be taken therefore to avoid this undesirable situation by appropriate forethought. 

Health effects data also are available for some petroleum fractions or process streams that are less heterogeneous. These materials are more representative of the fractions that may partition in the environment and are more useful for assessing health effects of intermediate and chronic exposure to petroleum hydrocarbons. These products are discussed further in Section 6.2. Additional discussion of these and also the more heterogeneous products is presented in Section 6.3. 

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