Spinning tension

LOY is characterized by low spinning tension, mostiy rheological effects, Httie orientation, amorphous stmcture, low tensde strength, and high elongation. The spun filament must be drawn, usually three to six times its initial length, and heat-treated before it develops useful properties. Nearly all PET staple is spun this way. 

The flyer-spinner and the up-spinner were mn in parallel for a number of years. There had been several trials to compare the properties of yams produced on the two systems. In general, the up-spun yams are more porous than the flyer-spun yams, which can be attributed to the different spinning tensions in the two spinning systems. The elastic modulus of the flyer-spun yams tends to be higher, but strain at break tends to be lower. However, the tenacity and work-to-rupture (toughness) of the yams spun on the two systems are similar. 

Flow processes iaside the spinneret are governed by shear viscosity and shear rate. PET is a non-Newtonian elastic fluid. Spinning filament tension and molecular orientation depend on polymer temperature and viscosity, spinneret capillary diameter and length, spin speed, rate of filament cooling, inertia, and air drag (69,70). These variables combine to attenuate the fiber and orient and sometimes crystallize the molecular chains (71). 

J. L. Cayais, R. S. Schecter, and W. H. Wade, The Measurement of Fow Intefacial Tension via the Spinning Drop Technique, Dept, of Chemistry and... 

Kelley spinners, when used as tension members An adapter between the swivel and the kelley that spins the kelley for rapid attachment and disattachment to joints of drill pipe. 

The first use of PAs was in fiber applications, in which fibers were produced by melt spinning. These materials have a high strength and good wear resistance and can be easily dyed. The tension stiffening effect of the PA melt made the production of fibers witii homogeneous thickness possible. 

Tests were performed at 75°C using a University of Texas Model 500 spinning drop tensiometer. Active surfactant concentration in the aqueous phase prior to addition of the oil phase was 0.5% wt. Interfacial tension values are the average of duplicate or triplicate determinations. 

The dynamic interfacial tension behavior of reacting acidic oil-alkaline solutions has been studied for both an artificially acidified synthetic oil and a real crude oil at various concentrations [131,132] with either a drop volume tensiometer or a spinning drop tensiometer. 

The spinning drop technique measures the shape of the oil drop in the flooding solution in a capillary tube. An automatic measuring system has been developed by combining a video-image analysis, an automatic recording system, and a computer for calculation of the interfacial tension [1865]. 

The effectiveness of a crude oil demulsifier is correlated with the lowering of the shear viscosity and the dynamic tension gradient of the oil-water interface. The interfacial tension relaxation occurs faster with an effective demulsifier [1714]. Short relaxation times imply that interfacial tension gradients at slow film thinning are suppressed. Electron spin resonance experiments with labeled demulsifiers indicate that the demulsifiers form reverse micellelike clusters in the bulk oil [1275]. The slow unclustering of the demulsifier at the interface appears to be the rate-determining step in the tension relaxation process. 

S. D. Ball. Comparison of transient interfacial tension behaviours of oiUalkaline systems as measured by the drop volume and spinning drop tensiometers. PhD thesis, Ottawa Univ, 1995. 

T. Yamazaki, K. Aso, H. Okabe, and Y. Akita. Automatic continuous-measuring system of interfacial tension by spinning drop technique. In Proceedings Volume. SPE Asia Pacific Conf (Yokohama, Japan, 4/25 /26), 2000. 

Oil/water interfacial tensions were measured for a number of heavy crude oils at temperatures up to 200°C using the spinning drop technique. The influences of spinning rate, surfactant type and concentration, NaCI and CaCI2 concentrations, and temperature were studied. The heavy oil type and pH (in the presence of surfactant) had little effect on interfacial tensions. Instead, interfacial tensions depended strongly on the surfactant type, temperature, and NaCI and CaCL concentrations. Low interfacial tensions (<0.1 mN/m) were difficult to achieve at elevated temperatures. 

The 0.4 cm i.d. capillary tubes were used instead of the recommended 0.2 cm i.d. 1 28 1 in order to facilitate the addition of highly viscous oils. Figure 2 shows the effect of spinning rate on the interfacial tension of an n-butanol/deionized water system us i ng two tube s izes. The dashed Ii ne represents the best fit for 15 data points measured using a 0.2 cm i.d. tube, where the mean interfacial tension is 1.76 mN/m (standard deviation of 0.02) with a range of 1.73 to 1.80 mN/m for speeds ranging from... 

Figure 2 Effect of spinning rate on the interfacial tension of r -butanol/water system at 30°C.

Figure 3 Effect of spinning rate on the interfacial tension of Clearwater bitumen/D20, and Sun Tech IV (5 g/L) and NaCI (10 g/L) system at 75°C.

It has been reported by Celik and Somasundaran T381 that the interaction of divalent (and trivalent) cations with sulfonate surfactants causes surfactant precipitation followed by dissolution of the precipitate at higher concentrations. The precipitate redissolution phenomenon is not observed with monovalent ions. Indeed, some surfactant precipitation in the spinning drop tube was observed above concentrations corresponding to the first minimum of Figure 8 it is not known whether redissolution took place at higher concentrations resulting in the second tension minimum. 

The interfacial shear viscosities are measured by the deep channel viscous traction surface viscometer (5) at the Illinois Institute of Technology. The oil-water equilibrium tensions are measured by either the spinning drop or the du Nouy ring (6) method. 

For effective demulsification of a water-in-oil emulsion, both shear viscosity as well as dynamic tension gradient of the water-oil interface have to be lowered. The interfacial dilational modulus data indicate that the interfacial relaxation process occurs faster with an effective demulsifier. The electron spin resonance with labeled demulsifiers suggests that demulsifiers form clusters in the bulk oil. The unclustering and rearrangement of the demulsifier at the interface may affect the interfacial relaxation process. 

Interfacial Tension (IFT) Measurements. All IFT measurements were done using a University of Texas Model 300 Spinning Drop Interfacial Tensiometer. The basic principle is to introduce a drop (about 2 p ) of an oil sample into a glass capillary tube (1.5 mm I.D., 78 mm long) filled with the aqueous medium. The tube is then spun about its main axis. The oil drop will elongate to a length determined by the IFT value of the system. Details of the theory and application can be found elsewhere (15.16). According to the equipment manufacturer, the formula used to calculate IFT value is ... 

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