Displacement mechanism, efficiency

Analysis ofthe kinetic data shows that the barium salt of 7, as well as the analogous salts of its higher homologues, perform much less efficiently than 4-Ba. The Ba complex of 7 turns over with a very low efficiency, caused by the extreme slowness of the deacylation step. Only a minor fraction ofthe liberated pNPOH in the steady-state phase is due to the expected double displacement mechanism. A larger fraction is most likely ascribable to the metal ion not sequestered by 7, and thereby available in solution for electrophilic assistance to direct methanolysis of the ester reactant. 

The results obtained with C19 and as model soils suggested that the crystal form of the hydrocarbon can affect surfactant penetration and hence removal. Hexacosane (C26), with a melting point of 57 °C, allows investigation of the effect of temperature over a wider range than the systems described above. Additional details about the relationship of surfactant phase behavior to solid soil removal can be obtained, and the efficiency of the displacement mechanism can be explored further, using C2g as a model soil. 

Large reservoir features can influence wettability alteration of a reservoir by surfactants. The sweep efficiency of a reservoir can influence the quantity of surfactant that contacts the reservoir rock matrix. Wettability alteration may be limited by the permeability contrast and the displacement mechanism. For a highly fractured reservoir with capillary dominated oil displacement, only the water... 

On primed ssDNA templates, AMV RTase has an initial polymerization rate comparable to that of Pol I. AMV RTase can use nicked or activated dsDNA as templates for DNA synthesis, most likely by a strand displacement mechanism (25). Compared with the primed ssDNA templates, nicked or activated DNA is used at 60% efficiency. Compared with natural RNAs, certain DNAs (e.g., activated calf thymus DNA) are over 100-fold more efficiently used as templates for AMV RTase (33). With DNA templates that require strand displacement or exonucleolytic activity, E. coli DNA Pol I is 100 times more active than AMV RTase. 

There are two principal mechanisms of enhanced oil recovery increasing volumetric sweep efficiency of the injected fluid and increasing oil displacement efficiency by the injected fluid. In both, chemicals are used to modify the properties of an injected fluid whether water, steam, a miscible gas such as CO2 or natural gas, or an immiscible gas, usually nitrogen. Poor reservoir volumetric sweep efficiency is the greatest obstacle to increasing oil recovery (9). 

The large variety of displacement-type flmd-transport devices makes it difficult to list characteristics common to each. However, for most types it is correct to state that (1) they are adaptable to high-pressure operation, (2) the flow rate through the pump is variable (auxiliary damping systems may be employed to reduce the magnitude of pressure pulsation and flow variation), (3) mechanical considerations limit maximum throughputs, and (4) the devices are capable of efficient performance at extremely low-volume throughput rates. 

S.K. Sinha W.D. Patwardhan, Explosiv-stoffe 16 (10), 223-25 (1968) CA 70,49144 (1969) The mechanism causing the plateau effect in the combustion of proplnts with ad-mixt of Pb compds (ie, the independence of pressure of the combustion rate in a certain range) is discussed. This effect is caused by the transport of free Pb alkyl radicals from the foam zone to the fizz zone, which decomn there, causing a more efficient combustion, and increase the temp of this zone by reaction1 with NO. An increase of pressure is assumed to displace the free radicals from this zone because of the increase of the collision rate . this leads... 

B. licheniformis JF-2 and Clostridium acetogutylicum were investigated under simulated reservoir conditions. Sandstone cores were equilibrated to the desired simulated reservoir conditions, saturated with oil and brine, and flooded to residual oil saturation. The waterflood brine was displaced with a nutrient solution. The MEOR efficiency was directly related to the dissolved gas/oil ratio. The principal MEOR mechanism observed in this work was solution gas drive [505]. 

For example, consider a reservoir which has produced 40% of the oil originally in place. If an injection fluid contacts 70% of the reservoir and has an oil displacement efficiency of 70% of the remaining oil (42% of the oil originally in place) then the maximum enhanced oil recovery is 49% of the oil remaining in place or 29% of the oil originally present in the reservoir. (Trapping and other oil loss mechanisms are neglected in this simplified treatment.) Total oil recovery has increased to 69%. 

Fig. 8. Reconstruction of Young s modulus map in a simulated object. A 3D breast phantom was first designed in silico from MR anatomical images. Then a given 3D Young s modulus distribution was supposed with a 1 cm diameter stiff inclusion of 200 kPa (A). The forward problem was the computing of the 3D-displacement field using the partial differential equation [Eq. (5)]. The efficiency of the 3D reconstruction (inverse problem) of the mechanical properties from the 3D strain data corrupted with 15% added noise can be assessed in (B). The stiff inclusion is detected by the reconstruction algorithm, but its calculated Young s modulus is about 130 kPa instead of 200 kPa. From Ref. 44, reprinted by permission of Wiley-Liss, Inc., a subsidiary of John Wiley Sons, Inc.

Use of zwitterions is an alternative approach that provides more effective mobilization of protein zones across a wide pH gradient.83 For example, cathodic mobilization with a low-pi zwitterion enables efficient mobilization of proteins with pis ranging from 4.65 to 9.60. The proposed mechanism for zwitterion mobilization couples a pH shift at the proximal end of the tube with a displacement effect at the distal end as the zwitterion forms an expanding zone within the gradient at its pi. Effective zwitterion mobilization depends on the selection of the appropriate mobilization reagent. 

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