Factors affecting migration rates

1 Electric field. The movement of ions on the paper is caused by the potential difference applied across the paper. The important parameter determining the extent of migration (d) is the voltage gradient, i.e. the applied voltage (V) divided by the distance (L) between the electrodes  

The extent of the migration increases with the increase in the voltage gradient. The speed of migration has been found to quickly attain a constant 

The separation of two species of different electrophoretic mobility, after time, t, is given by 

During the course of electrophoresis current flows and as in electrolysis the products are oxygen and hydrogen. 

The migration rate of the solutes is controlled not only by the pH of the electrolyte but also by its concentration, normally referred to as its ionic strength. As the ionic strength of the buffer solution increases, it carries a higher proportion of the current, with a concomitant reduction in the 

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Adsorption Kinetics. In zeoHte adsorption processes the adsorbates migrate into the zeoHte crystals. First, transport must occur between crystals contained in a compact or peUet, and second, diffusion must occur within the crystals. Diffusion coefficients are measured by various methods, including the measurement of adsorption rates and the deterniination of jump times as derived from nmr results. Factors affecting kinetics and diffusion include channel geometry and dimensions molecular size, shape, and polarity zeoHte cation distribution and charge temperature adsorbate concentration impurity molecules and crystal-surface defects. 

Amplification of C emission upon excitation of CPE, relative to that upon direct excitation of C is an important advantage of CPE-based FRET sensors, which benefits from the rapid intrachain and interchain energy migration from CPE to C via FRET. The detection sensitivity of CCP-based DNA sensor thus is enhanced to an extent dependent on the signal amplification of C emission. Amplification factor is defined as the intensity ratio of the saturated CCP-sensitized C emission to the intrinsic C emission in the absence of CCP. To acquire large signal amplification, it is necessary to review the factors affecting the FRET process from CCP to C. Equation (1) describes the calculation of FRET rate (KVRi T) [67] ... 

Factors affecting rate and extent of migration in packaged foods. 

One of the more important factors affecting the isolation of radioactive waste is the rate of release of the radioactivity from the solid waste form to the environment. The most probable mechanism for release and transport of radioactivity from a solid waste form is by leaching of radioactive isotopes with groundwater. The objective of leach-testing various waste forms is to evaluate the rate at which specific hazardous radionuclides migrate from waste if and when the waste form comes in contact with groundwater. In this paper, measurement of leach rates of radioactive waste by a method which incorporates neutron activation is described. 

Although it is now almost fifty years since Speier and his colleagues first announced the chloroplatinic acid-catalyzed hydrosilation of olefins, we are still far from complete control of the chemistry. A particular problem is the suppression of double bond migration. A solution of this problem will require a more detailed understanding of the factors affecting the relative rates of P-hydride elimination from an alkyl group and of the reductive elimination of Si-H from a platinum silyl hydride complex. Another factor which is poorly understood is suppression of the irreversible reduction of the platinum catalyst to Pt° metal. Both of these problems can greatly increase costs of production of certain products. 

Migrating antistats are time-sensitive in their use. Time is required for the additive to migrate to the surface of the PO produrt and to attract moisture from the air and minimize static buildup. This migration may delay its reaching optimum antistatic effectiveness by days or weeks, especially with a crystalline polymer like PP. Other factors affect the migration rate, such as the presence of other additives, insufficient concentration of the antistat, and temperature. 

The rate theory of chromatography, also known as the van Deemter model, examines the factors affecting band broadening, which is the amount of dispersion of a sample as it migrates through a column. 

To carry out the technique, protein molecules are denatured and move through a polyacrylamide gel by electrophoresis to be sorted by molecular mass. Proteins with the highest molecular mass move through the gel more slowly under the influence of the applied electric field, but because different proteins have a variety of different shapes and charge distributions, the experiment must be carefully designed so that these factors do not affect the rate of displacement, and that mass is really the only parameter influencing migration rate. 

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