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Polymeric filament thinning and breakup in microchannels

The effects of elasticity on filament thinning and breakup are investigated in microchannel cross flow. When a viscous solution is stretched by an external immiscible fluid, a low 100 ppm polymer concentration strongly affects the breakup process, compared to the Newtonian case. Qualitatively, polymeric filaments show much slower evolution, and their morphology features multiple connected drops. Measurements of filament thickness show two main temporal regimes: flow- and capillary-driven. At early times both polymeric and Newtonian fluids are flow-driven, and filament thinning is exponential. At later times, Newtonian filament thinning crosses over to a capillary-driven regime, in which the decay is algebraic. By contrast, the polymeric fluid first crosses over to a second type of flow-driven behavior, in which viscoelastic stresses inside the filament become important and the decay is again exponential. Finally, the polymeric filament becomes capillary-driven at late times with algebraic decay. We show that the exponential flow thinning behavior allows a novel measurement of the extensional viscosities of both Newtonian and polymeric fluids.Comment: 7 pages, 7 figure

A Population-Based Ultra-Widefield Digital Image Grading Study for Age-Related Macular Degeneration-Like Lesions at the Peripheral Retina.

Our understanding of the relevance of peripheral retinal abnormalities to disease in general and in age-related macular degeneration (AMD) in particular is limited by the lack of detailed peripheral imaging studies. The purpose of this study was to develop image grading protocols suited to ultra-widefield imaging (UWFI) in an aged population

Rapid acid tests for cream

The Farrington rapid acid test has been employed for many years by the fluid milk industry for grading samples on the borderline of acidity set for their purchase. In performing the test, neutralizing solutions (containing phenolphthalein) used are of such strength that 1 dipper of solution added to 1 dipper (of the same size) of milk gives a pink mixture if the milk is 0.1 percent acid or less; 2 dippers of neutralizing solution grade at the 0.2 percent point and so on. By adjusting the neutralizing strength the grades corresponding to 1 and 2 dippers of neutralizing solution to 1 of milk can be made 0.2 and 0.4 percent, respectively, instead of 0.1 and 0.2 percent. This is the strength of the solution used for cream grading

Chemistry of butter and butter making I. A comparison of four methods for the analysis of butter with an explanation of a discrepancy found to exist in the fat determinations

1. A modification of the A. O. A. C. method for complete butter analysis is described. The method is considered applicable for use in control laboratories, in which eight or more samples are analyzed at a time. 2. This method, together with the Kohman and Mojonnier analyses for butter, was compared with the A. O. A. C. method as a standard. The modified official and the Kohman methods check closely with the A. O. A. C. method for all constituents of butter. With the 50 samples analyzed in duplicate the fat content was 0.22 percent lower by the Mojonnier method (abnormal values not included-see table I ) than by the A. O. A. C. method. About 10 percent of the Mojonnier analyses varied widely from the duplicates and from the A. O. A. C. method. 3. The variation between duplicates is attributed (a) to peculiarities in the emulsification of the fat in the extraction flasks, which caused incomplete extraction, and (b) to a blowing out of ether-fat solution around the stoppers when these were removed or to both. 4. Data are presented which show that the value by which normal Mojonnier fat determinations are lower than the A. O. A. C. method is equivalent to the fatty acids, which are not extracted in the Mojonnier procedure but which appear as fat with the A. O. A. C. analysis. It is further shown that this difference was larger, as the rancidity of the butter increased. 5. The modified official method is a rapid method and is considered sufficiently accurate for the analysis of good quality butter in control laboratory work. Likewise the A. O. A. C. method is considered to be accurate as an analytical standard for the analysis of good quality butter. The Kohman method as outlined is a rapid method sufficiently accurate for plant use. All three methods give values for fat which are too high by an appreciable amount for the analysis of rancid butter. 6. The Mojonnier and the la-gram extraction methods give a closer approximation of the true fat value of rancid butter than do the dry extraction methods (A. O. A. C., modified official and Kohman)

Deep shower interpretation of the cosmic ray events observed in excess of the Greisen-Zatsepin-Kuzmin energy

We consider the possibility that the ultra-high-energy cosmic ray flux has a small component of exotic particles which create showers much deeper in the atmosphere than ordinary hadronic primaries. It is shown that applying the conventional AGASA/HiRes/Auger data analysis procedures to such exotic events results in large systematic biases in the energy spectrum measurement. SubGZK exotic showers may be mis-reconstructed with much higher energies and mimick superGZK events. Alternatively, superGZK exotic showers may elude detection by conventional fluorescence analysis techniques.Comment: 22 pages, 5 figure

INTEGRAL high energy behaviour of 4U 1812-12

The low mass X-ray binary system 4U 1812-12 was monitored with the INTEGRAL observatory in the period 2003-2004 and with BeppoSAX on April 20, 2000. We report here on the spectral and temporal analysis of both persistent and burst emission. The full data set confirms the persistent nature of this burster, and reveals the presence of emission up to 200 keV. The persistent spectrum is well described by a comptonization (CompTT) model plus a soft blackbody component. The source was observed in a hard spectral state with a 1-200 keV luminosity of 2*10^(36) ergs/s and L/LEdd~1% and no meaningful flux variation has been revealed, as also confirmed by a 2004 RXTE observation. We have also detected 4 bursts showing double peaked profiles and blackbody spectra with temperatures ranging from 1.9 to 3.1 keV.Comment: 6 pages, 4 figures. Accepted for publication by A&