Viscosity unit conversion

A number of arbitrary viscosity units have also been used. The most common has been the Saybolt Universal second (SUs) which is simply the time in seconds required for 60 mL of oil to empty out of the cup in a Saybolt viscometer through a carefully specified opening. Detailed conversion tables appear in ASTM D2161, approximation of kinematic viscosity V in mm /s(= cSt) can be made from the relation shown in equation 8 ... 

The flow rate data can also be used to estimate the permeability of the subsurface. The required additional parameter is the value of air viscosity, i.e., pa = 1.83 x 10 4 g/(cms). The intrinsic permeability of soil is calculated from equations 14.16 and 14.15 and is found to be K = 1.34 x 10 8cm2. Care should be taken to perform the appropriate unit conversions when using Equation 14.15. 

At 0.27 hp (0.20 kW), a constant viscous power number can be used to predict an apparent viscosity, with the aid of a 6.11 x 1CV15 units-conversion factor ... 

The cement slurry that is contained in a cylindrical cup is sheared by the relative movement of a paddle (either the cup or the paddle can be rotated). The torque necessary to maintain the paddle in a fixed position or to rotate it at a specified rotational speed (150 rpm) is recorded as a function of time while the slurry is submitted to a given temperature and pressure history. The torque reading, after proper calibration, is converted to a consistency expressed in Bearden units (Be). A simple conversion of this unit to a common viscosity unit cannot be done with non-Newtonian fluids. 

Pascal second (pascal-second, Pa-s) n. The SI unit of dynamic (absolute) viscosity, equal to INs/m. Some conversions of older viscosity units (of which there is a bewildering plethora) to Pa-s are given in the appendix. When shear stress t assumes its alternate identify, momentum flux, the pascal-second is interpreted as Ikg/ms). 

COMMENTS The reader should verify the unit conversion in this example, as it is not straight forward. As discussed, temperature, concentration, and other factors can drastically affect the ionic mobihty of a species. For example, we would expect the solution conductivity to increase with temperature by decreasing solution viscosity, and increase with ionic concentration. The concentration effect will reach a peak value at relatively low concentrations however, where ion-ion interactions begin to become important and reduce concentrated solution conductivity. 

In a single stage, without liquid recycle, the conversion can be optimized between 60 and 90%. The very paraffinic residue is used to make lubricant oil bases of high viscosity index in the range of 150 N to 350 N the residue can also be used as feedstock to steam cracking plants providing ethylene and propylene yields equal to those from paraffinic naphthas, or as additional feedstock to catalytic cracking units. 

TABLE 2.13 Viscosity Conversion Table Centistokes to Saybolt, Redwood, and Engler units. 

Although bulk polymerization of acrylonitrile seems adaptable, it is rarely used commercially because the autocatalytic nature of the reaction makes it difficult to control. This, combined with the fact that the rate of heat generated per unit volume is very high, makes large-scale commercial operations difficult to engineer. Lastiy, the viscosity of the medium becomes very high at conversion levels above 40 to 50%. Therefore commercial operation at low conversion requires an extensive monomer recovery operation. 

Routh and Russel [10] proposed a dimensionless Peclet number to gauge the balance between the two dominant processes controlling the uniformity of drying of a colloidal dispersion layer evaporation of solvent from the air interface, which serves to concentrate particles at the surface, and particle diffusion which serves to equilibrate the concentration across the depth of the layer. The Peclet number, Pe is defined for a film of initial thickness H with an evaporation rate E (units of velocity) as HE/D0, where D0 = kBT/6jT ir- the Stokes-Einstein diffusion coefficient for the particles in the colloid. Here, r is the particle radius, p is the viscosity of the continuous phase, T is the absolute temperature and kB is the Boltzmann constant. When Pe 1, evaporation dominates and particles concentrate near the surface and a skin forms, Figure 2.3.5, lower left. Conversely, when Pe l, diffusion dominates and a more uniform distribution of particles is expected, Figure 2.3.5, upper left. 

This equation defines the permeability (K) and is known as Darcy s law. The most common unit for the permeability is the darcy, which is defined as the flow rate in cm3/s that results when a pressure drop of 1 atm is applied to a porous medium that is 1 cm2 in cross-sectional area and 1 cm long, for a fluid with viscosity of 1 cP. It should be evident that the dimensions of the darcy are L2, and the conversion factors are (approximately) 10 x cm2/darcy C5 10-11 ft2/darcy. The flow properties of tight, crude oil bearing, rock formations are often described in permeability units of millidarcies. 

Staudinger, the final speaker, presented a broad array of data on polymerization, hydrogenation, comparisons of viscosity, melting points, and solubility of polymers. He pointed out that in the conversion of polystyrene to hexahydropolystyrene, and polyindene into hexahydropolyindene, the products retained their high molecular weight properties. Again, he maintained this proved "the monomers are united by main valencies" (62). 

Among them is the gel point conversion, if multifunctional units are present, as well as accompanying divergence of viscosity, onset of equilibrium elasticity modulus, etc. By comparing the results of modeling with experiment, one can verify to what extent the chemistry is affected by physical interactions which are practically always active in polymerizations. 

The conversion of dextran with 1,2-epoxy-3-phenoxypropane, epoxyoctane or epoxydodecane may be exploited for the preparation of amphiphilic dextran derivatives. Polymeric surfactants prepared by hydrophobic modification of polysaccharides have been widely studied, starting with the pioneering work of Landoll [261]. Neutral water-soluble polymeric surfactants can be obtained by reaction of dextran with 1,2-epoxy-3-phenoxypropane in 1 M aqueous NaOH at ambient temperature (Fig. 35, [229,233]). The number n of hydrophobic groups per 100 Glcp units varies between 7 and 22 depending on the reaction conditions. 2-Hydroxy-3-phenoxy propyl dextran ethers (DexP) behave like classical associative polymers in aqueous solution. In dilute solution, the intrinsic viscosity decreases significantly whereas... 

---