Rates of transfer from

Transfer of Disperse Dye on Polyester. A specimen of dyed polyester is placed in a standard dyebath with an equal weight of undyed polyester and the dyeing cycle completed. The rate of transfer from dyed to undyed fabric is compared to that obtained with a range of five standard dyes and the dye under test is given the same number as the dye it most closely resembles. 

If it is desired to calculate the rate of transfer from the overall concentration difference based on bulk-hquid compositions (x° — x), the appropriate overall coefficient Kl is related to the individual coefficients by the equation... 

For the simplest case of a two-surface enclosure in which surfaces 1 and 2 exchange radiation with each other only, then, assuming Tt > T2, >12 is the net rate of transfer from l, 2i or the rate of transfer to 2, 62-... 

Several workers have measured the rate of transfer from a liquid flowing down the inside wall of a tube to a gas passing countercurrently upwards. GILLILAND and SHERWOOD 36 vaporised a number of liquids including water, toluene, aniline and propyl, amyl and butyl alcohols into an air stream flowing up the tube. A small tube, diameter d — 25 mm and length = 450 mm, was used fitted with calming sections at the top and bottom, and the pressure was varied from 14 to about 300 kN/m2. 

Considerable work has been done on the behavior of pollutant species at air-water and air-soil interfaces. For example, wet and diy deposition measurements of various gaseous and particulate species have been made over a wide range of atmospheric and land-cover conditions. Still, the problem is of such complexity that species-dependent and particle-size-dependent rates of transfer from the atmosphere to water and soil surfaces are not completely understood. There is much to be learned about pollutant transfer at water-soil interfaces. Concern about groundwater contamination by mineral... 

The first row describes the condition if 1000 kg/h is emitted into the air. The result is similar to the Level II calculation with 19700 kg in air, 57 kg in water, 24 kg in soil and only 0.2 kg in sediment. It can be concluded that benzene discharged to the atmosphere has very little potential to enter other media. The rates of transfer from air to water and air to soil are both only about 0.4 kg/h. Even if the transfer coefficients were increased by a factor of 10, the rates would remain negligible. The reason for this is the value of the mass transfer coefficients which control this transport process. The overall residence time is 19.8 hours, similar to Level II. 

All of our measurements of proton transfer rates in acetonitrile have been done by various NMR techniques. One of the simplest has been used to measure the rates of transfer from cis-Os(CO) 2 to Et N and back again (21). Whereas a mixture of... 

Mass transfer rates within the porous residue are difficult to assess because it is impossible to define the shape of the channels through which transfer must take place. It is possible, however, to obtain an approximate indication of the rate of transfer from the particles to the bulk of the liquid. Using the concept of a thin film as providing the resistance to transfer, the equation for mass transfer may be written as ... 

In the case of local administration, lipoplexes are generally retained at the site of injection, with poor dispersion (22). In contrast to small emulsions or neutral liposomes, which immediately appear in the venous outflow perfusate following intratumoral injection, the appearance of cationic liposomes is highly restricted to the injection zone (22). The authors deduced that the determining factor altering the pharmacokinetic properties is not the rate of transfer from the interstitial space to the vascular site but rather the rate of transfer from the injection site to the well-vascularized region (23). 

However, the solubility in the blood is a major factor in determining the rate of absorption. For compounds with low solubility, the rate of transfer from alveolus to blood will be mainly dependent on blood flow (perfusion limited), whereas if there is high solubility in the blood, the rate of transfer will be mainly dependent on respiration rate (ventilation limited). 

This must be equal to the rate at which these atoms are incorporated into the particle locally at the interface. The rate at which B atoms in the matrix transfer to the particle across the a/(3 interface will be proportional to the local matrix concentration. The reverse rate of transfer from the particle to the matrix will be the same as the rate of transfer from the matrix to the particle that would occur under equilibrium conditions when detailed balance prevails. The net rate of transfer will then be... 

The concentration CAs is determined by the rate of reaction within the solid which must be equal to the rate of transfer from the liquid ... 

The Rapid Reaction. To analyze this limiting situation we shall assume the particles are sufficiently small so that the effectiveness factor is essentially one and that the rate of transfer from the bulk fluid to the individual catalyst particles is rapid in comparison with the rate of transfer between the fluidization phases. For the case of rapid reaction... 

The time resolution of this equipment is limited by the speed of mixing of the solutions, and the rate of transfer from the mixing chamber into the observation... 

The outward and inward H pathways have been shown to operate in p,s and ms time scales, respectively, so that their contributions to the total Aip formation can be easily measured. On the other hand, the rate of transfer from the Asp-96 carboxylic group to the Schiff base is of the same order of magnitude as the rate of reprotonation of this carboxylate by cytoplasmic ions. To measure the Atp contributions of these two steps separately, one may specifically decelerate the Asp-96 carboxylate reprotonation by decreasing the concentration in the medium. Under such conditions, both steps seem to make an almost equal contribution to energy conservation [20]. 

The net rate of transfer from the liquid to the crystal is the difference between frequency of jumps in each direction ... 

In this respect it is of vital interest to know the rate of transfer from the lithosphere to the biosphere. Both these major parts of a terrestrial ecosystem are physically overlapping in the top soil. Therefore it is advisable to look at the soil as on an interface which acts between the compartments like a sieve in both directions. 

The rate of transfer from the aquatic phase to the air is a complex function of several mass-transfer parameters including Henry s law constant (H) this is defined as the ratio of the vapour pressure of a compound to its solubility in water, and the value of H is of particular significance in many natural... 

To quantitate the lipid transfer activity of a protein, one measures the movement of labeled lipids from one membrane, the donor, to a second membrane, the acceptor. Typically, the donor and acceptor membranes are incubated in the presence and absence of transfer protein. After the incubation, the particles are separated and either the loss of radiolabeled lipids from the donor particles or the appearance of radiolabeled lipids in the acceptor particles is quantitated. The rate of lipid transfer in the presence of protein minus the transfer that occurs in the absence of protein is a measure of the lipid transfer activity of the protein. The transfer activity is expressed as a percent of the donor lipid transferred or the number of nmols lipid transferred per unit of time. To determine if the rate of lipid transfer also represents the rate of exchange, it must first be established that lipid exchange occurs between donors and acceptors. Exchange occurs when the rate of lipid transfer from donor to acceptor equals the rate of transfer from acceptor to donor or when the chemical composition of the donor and acceptor membranes does not change during the transfer reaction. 

Emissivity tg is therefore the ratio of the rate of energy transfer from the gas to the surface element to the rate of transfer from a black hemispherical surface of radius L and temperature Tg to the same surface element. Figure 14.11 shows how Eg for carbon dioxide varies with radius L and partial pressure pg. Figure 14.11 applies at a total pressure p of 1 atm Fig. 14,12 gives the correction factor for finding Eg at other total pressures. 

The first work to examine precursor effects in a quantitative manner was performed only recently by King [298]. It is based on the reversal of the kinetic model described in Sect. 3.2.2. The rate of transfer from the chemisorbed state to the precursor is given by... 

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