Phase wicking

Dukler, A. E. Moye Wicks III, and Cleveland, R. G. <4. I. Ch. E. Jl. 10 (1964) 38. Frictional pressure drop in two-phase flow. A comparison of existing correlations for pressure loss and holdup. 

FIGURE 6.2 Brenner and Niederwieser S-chamber (a) normal development, (b) continuous development 1 — mobile phase, 2 — wick, 3 — chromatographic plate with adsorbent layer face up, 4 — cover plate, 5 — support, 6 — heater, 7 — evaporation of the mobile phase. (From Brenner, M. and Niederwieser, A., Experientia 17, 237-238, 1961. With permission.)... 

FIGURE 6.3 Sequence developing chamber by Buncak 1 — support with mobile phase source (reservoir), 2 — holding frame, 3 — magnet holder, 4 — magnet, 5 — cover plate, 6 — TLC plate, 7 — wick with iron core, 8 — solvent entry. (From Buncak, P., GIT Fachz. Lab. (Suppl., Chromatographie), G-I-T-Verlag, Darmstadt, 3-8, 1982. With permission.)... 

Dukler, A. E., M. Wicks, and R. E. Cleveland, 1964, Frictional Pressure Drop in Two Phase Flow, B. 

Duckler AE, M Wicks III, RG Cleveland. Frictional pressure drop in two-phase flow B. An approach through similarity analysis. AIChE J. 10 44—51, 1964b. 

Similarly, when arrays of these test resonant cavities loaded with functionalized wicks for various toxins are phase-locked to the reference cavity as shown in Fig. 15.5 they can act as detectors for targeting various toxins as well as their precursors through an array of suitably tuned cavities with specifically functionalized nanotubes. By using the approach as demonstrated in this document, it has been shown that the apparatus can be used to successfully detect low levels of toxin vapors associated with the drag Methamphetamine, in a laboratory-controlled environment. Some of the results of this study are highly sensitive in nature and are not reported in this document. These results can be obtained by other avenues. 

Fig. 15.5 Arrays of cavities phase-locked to the reference cavity and loaded with functionalized wicks to specifically determine the toxin and its precursors...

Wick et al. [221,222] have applied Monte Carlo (MC) simulations to RPLC models composed of an n-hexadecane retentive phase with a water-methanol mobile... 

Wick, C.D., Siepmann, J.I., and Schure, M.R., Simulation studies on the effects of mobile-phase modification on partitioning in liquid chromatography, Anal. Chem., 76, 2886, 2004. 

Mass transfer controlled by diffusion in the gas phase (ammonia in water) has been studied by Anderson et al. (A5) for horizontal annular flow. In spite of the obvious analogy of this case with countercurrent wetted-wall towers, gas velocities in the cocurrent case exceed these used in any reported wetted-wall-tower investigations. In cocurrent annular flow, smooth liquid films free of ripples are not attainable, and entrainment and deposition of liquid droplets presents an additional transfer mechanism. By measuring solute concentrations of liquid in the film and in entrained drops, as well as flow rates, and by assuming absorption equilibrium between droplets and gas, Anderson et al. were able to separate the two contributing mechanisms of transfer. The agreement of their entrainment values (based on the assumption of transfer equilibrium in the droplets) with those of Wicks and Dukler (W2) was taken as supporting evidence for this supposition. 

Extensive treatments of general two-phase flow problems have been given in the monograph by Kutateladze and Styrikovich (K25) and in recent surveys by Dukler and Wicks (Dl7), and Scott (S4), all of which indicate clearly the important place of film flow in the over-all scheme of two-phase flow phenomena. Film flow is more amenable to detailed study than most other types of two-phase flow, and a detailed knowledge of the phenomena occurring in film flow (with or without an adjacent gas stream) would assist greatly in understanding many of the more complex types of two-phase flow and the mechanisms of heat and mass transfer in such flows. Numerous experimental studies have been made of various two-phase transfer processes, but these have led mainly to empirical correlations of more or less limited applicability. 

Attempts have been made to compare the experimentally measured pressure drops with various of the theories discussed in Section III, F and with the more generalized empirical two-phase friction-factor correlations of the type discussed by Dukler and Wicks (D17). Hewitt et al. (H10) have compared their experimental data for upward cocurrent flow with one such empirical correlation and with the theories of Anderson and Mantzouranis (A5) and of Dukler (D12) and Hewitt (H7). In most cases there was good qualitative agreement only. 

Deibler, K.D. 1999. Gas chromatography - olfactometry (GC/O) of vapor phases. In Flavor Chemistry Thirty Years of Progress (R. Ter-anishi, E.L. Wick, and I. Homstein, eds.) pp. 387-395. Kluwer Academic/Plenum Publishers, New York. 

Contaminants in the soil compartment are associated with the soil, water, air, and biota phases present. Transport of the contaminant, therefore, can occur within the water and air phases by advection, diffusion, or dispersion, as previously described. In addition to these processes, chemicals dissolved in soil water are transported by wicking and percolation in the unsaturated zone.26 Chemicals can be transported in soil air by a process known as barometric pumping that is caused by sporadic changes in atmospheric pressure and soil-water displacement. Relevant physical properties of the soil matrix that are useful in modeling transport of a chemical include its hydraulic conductivity and tortuosity. The dif-fusivities of the chemicals in air and water are also used for this purpose. 

Aboofazeli, R., Lawrence, C. B., Wicks, S. R., and Lawrence, M. J. (1994), Investigations into the formation and characterization of phospholipid microemulsions. Part 3. Pseudo-ternary phase diagrams of systems containing water-lecithin-isopropyl myristate and either an alkanoic acid, amine, alkanediol, polyethylene glycol alkyl ether or alcohol as cosurfactant, Int. J. Pharm., Ill, 63-72. 

Another type of tank is the sandwidi unit in which the TLC plate is clamped horizontally b weoi two glass plates separated by gaskets. A wick at one edge of the TLC plate provides the solvoit res oir to develop the plate. The advantage of this system is that it uses less mobile phase, provides a more quickly saturated vapour system, and gives shorter running times. 

---