Factors influencing distribution

Representative plots of Ma°/Mtot for the dimerization reaction with varying values of the distribution parameters Km and KP are given in Figure 1 as a semilogarithmic plot. Values of the distribution parameters were chosen here in relation to a gel partition model, where the only factor influencing distribution is a molecular size function that is, Kx... 

After arriving at a particular organ, the free, unbound form of the drug is able to cross first the endothelial cells of the capillaries into the interstitial space, and subsequently the cellular membrane of the tissue. Capillary permeability is largely determined by (1) capillary structure and (2) the chemical nature of the drug. The membrane-related factors influencing distribution of drugs between blood plasma and tissues are essentially the same as those described previously between the GI tract and blood plasma. 

By contrast, the properties of the chemical become most significant in determining its tendency to move between compartments. Thermodynamic and kinetic factors influence distribution and although natural systems are rarely reversible, such an assumption can provide an indication of the trend for movement between compartments. The primary objective, then, will be to predict the environmental distribution of an organic compound as a function of its physical chemical properties using the following approach ... 

To document the future distribution network requirements, it is not only important to understand the factors influencing distribution but also to understeuid the meu keting strategies and sales forecast. The following list identifies questions that should be answered by meu keting and sales ... 

In the rat, the observed effects of oral LD50 reflect both the intrinsic toxicity at the ultimate biophase site of action and the factors influencing distribution, membrane transport, protein binding, metabolism and excretion. The manifestation of acute mammalian toxicity is hence a much more complex response than can be described with the use of log alone, although individual processes such as bioavailability and adsorption depend on lipophilic-ity. The fit to a common QSAR model requires that each of these processes has similar structural dependences, qualitatively and quantitatively, within a given class of compounds. If a different process becomes predominant (i.e. rate limiting), the structure-toxicity relationship must alter thus the compound will be an outlier even when the principal mechanism of intrinsic toxicity remains the same. 

Liquid Holdup The major factor influencing this property is the liquia flow rate, but the shape, size, and wetting characteristics of the particles and the gas rate and the initial distribution of liquid also enter in. One of the simpler correlations is that of Midoux et al. (J. 

Airborne contaminant movement in the building depends upon the type of heat and contaminant sources, which can be classified as (1) buoyant (e.g., heat) sources, (2) nonbuoyant (diffusion) sources, and (d) dynamic sources.- With the first type of sources, contaminants move in the space primarily due to the heat energy as buoyant plumes over the heated surfaces. The second type of sources is characterized by cimtaminant diffusion in the room in all directions due to the concentration gradient in all directions (e.g., in the case of emission from painted surfaces). The emission rare in this case is significantly affected by the intensity of the ambient air turbulence and air velocity, dhe third type of sources is characterized by contaminant movement in the space with an air jet (e.g., linear jet over the tank with a push-pull ventilation), or particle flow (e.g., from a grinding wheel). In some cases, the above factors influencing contaminant distribution in the room are combined. 

Brecevic, Lj. and Kralj, D., 1989. Factors influencing the distribution of hydrates in calcium oxalate precipitation. Journal of Crystal Growth, 97, 460M68. 

Many of the spinel-type compounds mentioned above do not have the normal structure in which A are in tetrahedral sites (t) and B are in octahedral sites (o) instead they adopt the inverse spinel structure in which half the B cations occupy the tetrahedral sites whilst the other half of the B cations and all the A cations are distributed on the octahedral sites, i.e. (B)t[AB]o04. The occupancy of the octahedral sites may be random or ordered. Several factors influence whether a given spinel will adopt the normal or inverse structure, including (a) the relative sizes of A and B, (b) the Madelung constants for the normal and inverse structures, (c) ligand-field stabilization energies (p. 1131) of cations on tetrahedral and octahedral sites, and (d) polarization or covalency effects. ... 

These complicating factors influence not only the middle composition and composition distribution curves of copolymers, but also the kinetic parameters of copolymerization and the molecular weight of copolymers. An understanding of these complicating factors makes it possible to regulate the prosesses of copolymerization and to obtain copolymers with different characteristics and, therefore, with various properties. 

Xin and co-workers modified the alkaline EG synthesis method by heating the metal hydroxides or oxides colloidal particles in EG or EG/water mixture in the presence of carbon supports, for preparing various metal and alloy nanoclusters supported on carbon [20-24]. It was found that the ratio of water to EG in the reaction media was a key factor influencing the average size and size distribution of metal nanoparticles supported on the carbon supports. As shown in Table 2, in the preparation of multiwalled carbon nanotube-supported Pt catalysts... 

For cases where the growth period is the same as the residence time in the reactor, as in polycondensation processes, the residence time distribution is the dominant factor influencing the molecular weight distribution. In this case one obtains a broader molecular weight distribution from a CSTR than from a batch reactor. Figure 9.12 [also taken from Denbigh (11)] indicates the type of behavior expected for systems of this type. 

Rutherford, T.A., Mamiya, Y. and Webster, J.M. (1990) Nematode-induced pine wilt disease factors influencing its occurrence and distribution. Forest Science 36, 145-155. 

Figure 1. Schematic illustration of factors influencing the production and migration of radon in soils and into buildings. Geochemical processes affect the radium concentration in the soil. The emanating fraction is principally dependent upon soil moisture (1 0) and the size distribution of the soil grains (d). Diffusion of radon through the soil is affected primarily by soil porosity ( ) and moisture content, while convective flow of radon-bearing soil gas depends mainly upon the air permeability (k) of the soil and the pressure gradient (VP) established by the building.

Moore, J.W. 1981. Influence of water movements and other factors on distribution and transport of heavy metals in a shallow bay (Canada). Arch. Environ. Contam. Toxicol. 10 715-724. 

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