Dynes

The interfacial tension is usually expressed in mN/m or dynes/cm. It measures the tendency for a liquid to form an interface having the least area. The interfacial tension decreases as the temperature Increases. 

Viscosity is measured in poise. If a force of one dyne, acting on one cm, maintains a velocity of 1 cm/s over a distance of 1 cm, then the fluid viscosity is one poise. For practical purposes, the centipoise (cP) is commonly used. The typical range of gas viscosity in the reservoir is 0.01 - 0.05 cP. By comparison, a typical water viscosity is 0.5 -I.OcP. Lower viscosities imply higher velocity for a given pressure drop, meaning that gas in the reservoir moves fast relative to oils and water, and is said to have a high mobility. This is further discussed in Section 7. 

Dyne, unit of force dyn Equilibrium position vector Ro... 

D = mean droplet diameter (pm) s = surface tension (dyne- cm" ) d = density of liquid (g- cm" )... 

The following are approximate (in dyne cm ) versus y datat for three different samples of polyisoprene in tetradecane solutions of approximately the same concentration ... 

The authors of this research selected units which could be written with maximum simplification to report their results. We must replace the factors which have canceled out. Assuming that the cgs system of units was used throughout, we note that possible units for H are grams per square centimeter and possible unts for C2 are grams per cubic centimeter, which yield the required units for n/c2 Note that these units of H must be multiplied by the gravitational constant to give H in dynes per square centimeter ... 

Coulomb s law. This relationship poses no particular difficulties as a qualitative statement the problem arises when we attempt to calculate something with it, since the proportionality constant depends on the choice of units. In the cgs system of units, the electrostatic unit of charge is defined to produce a force of 1 dyne when two such charges are separated by a distance of 1 cm. In the cgs system the proportionality factor in Coulomb s law is unity and is dimensionless. For charges under vacuum we write... 

Fig. 12. Tensile strength vs draw ratio (6) 0.42 melt index spun at 50 m /min, B, and 500 m /min, A, A 12.0 melt index spun at 100 m /min, , O and 500 m /min, , <). Open symbols = cold drawn and annealed at 140°C filled symbols = drawn at 140°C. To convert GN/m to dyne/cm, multiply by...

Process effectiveness depends on maintaining an ultralow (ca 10 ° N/m (10 dynes/cm)) interfacial tension between the injected surfactant slug and the cmde oil (213). The effect of petroleum composition on oil solubilization by surfactants has been the subject of extensive study (214). 

An alternative to this process is low (<10 N/m (10 dynes /cm)) tension polymer flooding where lower concentrations of surfactant are used compared to micellar polymer flooding. Chemical adsorption is reduced compared to micellar polymer flooding. Increases in oil production compared to waterflooding have been observed in laboratory tests. The physical chemistry of this process has been reviewed (247). Among the surfactants used in this process are alcohol propoxyethoxy sulfonates, the stmcture of which can be adjusted to the salinity of the injection water (248). 

D. L. Van Dyne, M. G. Blase, and K. D. Carlson, Industrial Feedstocks and Productsfrom High ErudcMdd Oil, University of Missouri-Columbia, Columbia, Mo., 1990, 30 pp. 

Viscosity is equal to the slope of the flow curve, Tf = dr/dj. The quantity r/y is the viscosity Tj for a Newtonian Hquid and the apparent viscosity Tj for a non-Newtonian Hquid. The kinematic viscosity is the viscosity coefficient divided by the density, ly = tj/p. The fluidity is the reciprocal of the viscosity, (j) = 1/rj. The common units for viscosity, dyne seconds per square centimeter ((dyn-s)/cm ) or grams per centimeter second ((g/(cm-s)), called poise, which is usually expressed as centipoise (cP), have been replaced by the SI units of pascal seconds, ie, Pa-s and mPa-s, where 1 mPa-s = 1 cP. In the same manner the shear stress units of dynes per square centimeter, dyn/cmhave been replaced by Pascals, where 10 dyn/cm = 1 Pa, and newtons per square meter, where 1 N/m = 1 Pa. Shear rate is AH/AX, or length /time/length, so that values are given as per second (s ) in both systems. The SI units for kinematic viscosity are square centimeters per second, cm /s, ie, Stokes (St), and square millimeters per second, mm /s, ie, centistokes (cSt). Information is available for the official Society of Rheology nomenclature and units for a wide range of rheological parameters (11). 

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