Recovery curves after contact

Figure 11. Recovery curves after contact deformation of polymers.

Mechanistic interpretations The results of the dynamic and equilibrium displacement experiments are used to evaluate and further define mechanisms by which alkaline floods increase the displacement and recovery of acidic oil in secondary mode and the tertiary mode floods. The data sets used in the mechanistic interpretations of alkaline floods are (a) overall and incremental recovery efficiencies from dynamic and equilibrium displacement experiments, (b) production and effluent concentration profiles from dynamic displacement experiments, (c) capillary pressure as a function of saturation curves and conditions of wettability from equilibrium displacement experiments, (d) interfacial tension reduction and contact angle alteration after contact of aqueous alkali with acidic oil and, (e) emulsion type, stability, size and mode of formation. These data sets are used to interpret the results of the partially scaled dynamic experiments in terms of two-stage phase alteration mechanisms of emulsification followed by entrapment, entrainment, degrees and states of wettability alteration or coalescence. 

When a recovery well is located within a contaminant plume and the pump is started, the initial concentration of contaminant removed is close to the maximum level during preliminary testing. As the pump continues to operate, cleaner water is drawn from the plume perimeter through the aquifer pores toward the recovery well. Some of the contaminant is released from the soil into the water in proportion to the equilibrium coefficient. For example, if the Kd is 1000, at equilibrium, 1 part is in the water and 1000 parts are retained in the soil. If the water-soil contact time is sufficient, complete equilibrium will be established. After the first pore volume flush (theoretically), the concentration in the water will be 0.9 and that on the soil will be 999. With each succeeding flush, the 1000 1 ratio will remain the same. If the time of water-soil contact is not sufficient to establish equilibrium, the recovered water will contain a lesser concentration. A typical decline curve is shown on Figure 9.2. Note the asymptotic shape of the curve where the decline rate is significantly reduced. 

Results. The results in Table 4.6 show the detection and percentage recovery of each metal added. Analysis before and after stirring using the slurry technique was used to determine the insoluble fillers and plastisers, etc. Plastics that are surface treated with metals as colorants or protective coating may be contacted with 2.0 M HNO3 or 2.0 M HC1 for a period of time to dissolve the metal salt, and analysed against standard calibration curves prepared in the appropriate aqueous solution. 

Passive adsorption of stearic acid, a classic lubricant additive, from an alkane solution on metal oxides has been studied by several authors 34,35). Over a period of 1 minute to several days (probably depending on the reactivity of the surface) stearic acid self-assembles on the surface to form a dense monolayer. This is an alternative method to form a methylated surface. Figure 6b shows FRAP curves obtained at different incubation times between the SA - hexadecane solution and the sapphire surface. Unlike the previous experiment the system was not dismantled and readjusted between different measurements, eliminating errors due to alignment. The fluorescence recovery appears faster after a few days of contact compared to short times of incubation, revealing that hexadecane slips on the adsorbed stearic acid layer formed in situ. 

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