Exudation kinetics

Fig. 1,11. Exudation kinetics of PI from PE film - vacuum oil samples in response to oil concentration in CM (1) 20wt% (2) 40% (3) 60wt%...

It has been proven in [107] that the exudation kinetics of the inhibiting liquid from film samples produced of a mixture of PE - - mineral oil - - contact Cl (Vital, GRM) by pressing under the polymer viscous flow temperature is... 

D. L. Jones, A. M. Prabowo, and L, V, Kochian, Kinetics of malate tran.sport and decomposition in acid soils and isolated bacterial populations the effect of microorganisms on root exudation of malate under A1 stress. Plant Soil /((2 239 (1996). 

Water-soluble root exudates are most frequently collected by immersion of root systems into aerated trap solutions for a defined time period (Fig. 1 A). The technique is easy to perform and permits kinetic studies by repeated measurements over time using the same plants. While it is possible to get a first impression about qualitative exudation patterns and even quantitative changes in response to different preculture conditions, the technique also includes several restrictions that should be taken into account for the interpretation of experimental data. 

Due to the usual diversity of components in the medium, there will be a need to consider that the species taken up interacts with other species while diffusing towards the organism surface (see Figure 19). In some cases (as in the aquatic prokaryotes that exudate Fe chelators called siderophores to improve the availability of Fe see Chapter 9 in this volume), the medium is modified on purpose by the organisms [11,47-49], A simple model for this interaction assumes the complexation of M with a ligand, with elementary interconversion kinetics between the free and complexed forms ... 

Ochs, M., Brunner, I., Strumm, W. Cosovic, B. (1993). Effects of root exudates and humic substances on weathering kinetics. Water Air and Soil Pollution, 68, 213-29. 

At pH values close to 7.0 the cowpea protein solubilized and formed the continuous phase in which raw starch granules were dispersed. On heating, the granules absorbed water and as they swelled they exuded some amylose into the continuous matrix prior to the protein denaturation. The higher transition temperature of the protein compared to that of starch created the environment for the leaching of amylose into the solution of the protein (Muhrbeck and Eliasson, 1991). The coexistence of the protein and the amylose in the continuous phase may be responsible for the distinct kinetic pattern in the observed development of G in the cowpea protein-starch blends. For such a system, the protein/starch ratio (R) would reflect the protein/ amylose ratio in the continuous matrix and may be considered to be an important parameter for assessing G of the mixture gels. 

CdCN2 decomposed [68] in vacuum within the interval 865 and 989 K to yield metal, cyanogen and nitrogen E = 159 kJ mol ) for which the ur-time exudes were fitted by the contracting volume equation. The reaction in oxygen, which formed metal oxide, nitrogen and carbon dioxide = 82 kJ mol ) followed the same kinetic model and both reactions are believed to proceed by an interface advance mechanism. 

Jones, D.L., Prabowo, A.M., Kochian, L.V., 1996. Kinetics of malate transport and decomposition in acid soUs and isolated bacterial populations The effect of microorganisms on root exudation of malate under Al stress. Plant Soil 182, 239-247. 

The values for the exudation rate F, interaction coefficient (A), buffer power of exudate in soil b and the decomposition rate constant for the exudate k were adopted from Kirk (1999). The value of the forward rate constant was estimated from Scheckel and Sparks (2001), who evaluated kinetic adsorption data of Ni to different minerals where ranged from 2.5 x 10 to 9.78 X 10 s For the simulation, an average value of 5.00 x 10 was used. This value also coincides with the values that Kirk and Staunton (1989) suggested for the kinetic adsorption of Q to soil, where the values ranged from lO" to 10 2 s f This same value was assumed for the rate constant for the two-stage sorption model, a2- The fraction of type 1 sites (F ) was assumed to be 0.3. Table 7 summarizes all input parameter values. 

This requirement has been taken into account in an algorithm [5, 6] aimed at optimizing formulations of wrapping films based on plasticized PE contained in PHC in the form of VCI. The algorithm is based on the information on isolation kinetics of Cl from films of different compositions and includes the design of Cl flow balance. Being dissolved in a condensed electrolyte layer on the metal surface or found as a vapor in the air gap between the film and metal, it is spent on the formation of an adsorption protecting layer on the metal surface. A part of the Cl is kept by the exudate and evaporates in the environment. 

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