Fibers fiber phase

In the dyeing process absorption from the dyebath solution to the fiber eventually stops when an equiHbrium exists between the dye in the fiber phase and the dye in the solution phase. At this point by definition (no movement of dye molecules), therefore... 

Influence of the Fiber. In order for a dye to move from the aqueous dyebath to the fiber phase the combination of dye and fiber must be at a lower energy level than dye and water. This in turn implies that there is a more efficient, lower energy sharing of electrons or intramolecular energy forces, and there are a number of mechanisms that allow this to happen. 

There is a strong attraction between dye and fiber when oppositely charged. The mobile charged dyestuff chromogen "moves" from the external water phase to the stationary internal fiber phase. For like-charged entities repulsion occurs, and no movement of dyestuff from the water to the fiber takes place. 

A reactive dye for ceUulose contains a chemical group that reacts with ionized hydroxyl ions in the ceUulose to form a covalent bond. When alkaH is added to a dyebath containing ceUulose and a reactive dye, ionization of ceUulose and the reaction between dye and fiber is initiated. As this destroys the equihbrium more dye is then absorbed by the fiber in order to re-estabUsh the equUibrium between active dye in the dyebath and fiber phases. At the same time the addition of extra cations, eg, Na+ from using Na2C02 as alkaH, has the same effect as adding extra salt to a direct dye. Thus the addition of alkaH produces a secondary exhaustion. 

The equHibrium deprotonation of ceHulose in alkaU can be represented as foHows, where H ] is the concentration of hydrogen ions in the internal fiber phase. 

Polymer types employed Urethanes polyolefins (fiber phase) Urethanes polyolefins (fiber phase) Urethanes Various... 

We have chosen to call the two phases resin and fiber. Each phase will be denoted by subscript r and respectively. A similar phase function (i.e., Yf) can be defined for the fiber phase. It should be noted that if the fiber phase is stationary Y is not a function of time. 

As mentioned earlier, the expression forfd is obtained under conditions of no inertia. If we further assume the resin is Newtonian (i.e., r = p[V Ur + V / ])) and the fiber phase is stationary, then Equation 5.25 can be simplified to the well-known Brinkman equation [22],... 

Since the fiber phase is not stationary, the surface integral cannot be set to zero without further considerations. As shown earlier, dBr/dt = 1/V js Ur hids (see Eq. 5.10). Because der/dt = 0 in the IP process, the contribution of the surface integral to the overall mass balance is negligible. Based on this observation Equation 5.50 can be simplified mid the appropriate equation for a conservation of mass in this process can be obtained (i.e., V Ur) = 0). Using this, Equation 5.18 can be simplified and the appropriate species balance equation for the IP process can be obtained. This equation is similar to the equation obtained for the RTM process. 

The movement of the fiber phase has to be specifically taken into consideration in the momentum transfer equation. Hence, in absence of significant inertial forces (i.e., Rep < l)3 Equation 5.28 must be modified to account for the movement of the fiber phase,... 

The practical characteristic of a dyestuff is that when a textile is immersed in a solution containing a dye. the dye preferentially adsorbs onto and diffuses into the texiile. The thermodynamic equations defining this process have been reviewed in detail. The driving force for this adsorption process is the difference in chemical potential between the dye In the solution phase and the dye in the fiber phase. In practice it is only necessary to consider changes in chemical potential and to understand that the driving force is the reduction in free energy associated with the dye molecule moving from one phase to the other, as the molecule always moves to the siate of lowest chemical potential. 

There is a unique kSPMEfor each compound and fiber phase. 

Gas chromatography/olfactometry (GC/O) based on dilution analysis (e.g., CharmAna-lysis or Aroma Extraction Dilution Analysis) gives an indication of what compounds are most potent in the aroma of foods. The application of SPME to GC/O dilution analysis can be achieved by varying the thickness of the fiber phase and the length of exposure, resulting in various absorbant volumes. 

For example, Swift and Barr established the proton NMR data with 170 relaxation studies on frog skeletal muscles272. They also found that the water relaxation is enhanced in muscles in comparison with pure water272. Cooke and Wien273 observed on partially dried rabbit psoas fibers two phases of muscle water a small phase, less than 4—5% of the total water, which interacts strongly with the proteins and has short relaxation times and a major phase. .. with longer relaxation times a major fraction of the intracellular water exists in a less mobile form than water in a salt solution 273. ... 

Bardstu, K.F., Ho, T.S., Rasmussen, K.E., Pedersen-Bjergaard, S. and Jonsson, J.A. (2007) Supported liquid membranes in hollow fiber liquid-phase microextraction (LPME) — Practical considerations in the three-phase mode. Journal of Separation Science, 30, 1364. 

Asymmetric Microporous Nonporous, skinned on microporous substrate Flat-sheet, tubular, hollow fiber Flat-sheet, tubular, hollow fiber Phase-inversion casting or spinning Phase-inversion casting or spinning Microfiltration, ultrafiltration, membrane reactors Reverse osmosis, gas separation, pervaporation, perstraction, membrane reactors... 

Because NL(t) has the same periodicity as A(t) the comb structure of the spectrum, as derived in section 3, is not affected. In an optical fiber self-phase modulation can be quite efficient even though the nonlinear coefficient in fused silica is comparatively small. This is because the fiber core carries a high intensity over an extended length. 

Bayer, S.G., Zumwalde, R.D., Brown, T.A., "Equipment and Procedures for Mounting Mi 11ipore Filters and Counting Asbestos Fibers by Phase Contrast Microscopy", 1-15 (July, 1969), U.S. Department of Health, Education and Welfare, Public Health Service, Bureau of Occupational Safety and Health,... 

As expected, the matrix deviatoric stresses will be relaxed away completely. Thereafter, the fiber phase sustains the entire deviatoric stress. As a consequence, in the asymptotic state... 

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