Thomas W. Taylorhttps://works.bepress.com/thomas_taylor/Recent works by Thomas W. Tayloren-usCopyright (c) 2020 All rights reserved.Thu, 20 May 1999 07:00:00 +00003600Particle Sizing in Strongly Turbid Suspensions with the One-Beam Cross-Correlation Dynamic Light-Scattering Techniquehttps://works.bepress.com/thomas_taylor/6/The utility of the one-beam cross-correlation dynamic light-scattering system for sizing small particles in suspension was previously limited by its small-intensity signal-to-baseline ratio for strongly turbid suspensions. We describe three improvements in the optical system and sample cell that raise the ratio to a value comparable with that of other cross-correlation dynamic light-scattering systems. These improvements are (i) using a square cross-sectional sample cell to minimize the attenuation of the incident beam and singly scattered light, (ii) placing a 200-mu m-wide slit between the sample cell and the detector fibers to mask off the region of weak single scattering and strong multiple scattering from the detectors' field of view, and (iii) aligning the center of the detectors' field of view with the region of strongest single scattering. We analyze a number of suspensions of polystyrene latex spheres with a diameter between 65 and 562 Ma in water using this improved one-beam instrument and find that the measured radius is determined in a 2-min data collection time to better than +/-10% for volume fractions of the suspended polystyrene latex spheres up to a few percent. (C) 1999 Optical Society of America.Thu, 20 May 1999 07:00:00 +0000https://works.bepress.com/thomas_taylor/6/ArticlesHybrid Reflection-Transmission Surface Light-Scattering Instrument with Reduced Sensitivity to Surface Sloshinghttps://works.bepress.com/thomas_taylor/3/A hybrid reflection-transmission surface light-scattering instrumental design is presented, examined theoretically, and tested experimentally. The purpose of the design is to reduce the sensitivity of the instrument to vibration in general and surface sloshing in particular while sacrificing Little performance. Traditional optical arrangements and two new optical configurations with varying trade-offs between slosh resistance and instrumental simplicity and accuracy are examined by use of Fourier optics methods. The most promising design was constructed and tested with acetone, ethanol, and water as subject fluids. The test involved backcalculation of the wave number of the capillary wave examined with the known physical parameters for the test fluids. The agreement of the computed wave number was +/-1.4%. (C) 1997 Optical Society of America.William V. Meyer et al.Mon, 20 Oct 1997 07:00:00 +0000https://works.bepress.com/thomas_taylor/3/ArticlesFiber-Optics Surface-Light-Scattering Spectrometerhttps://works.bepress.com/thomas_taylor/2/We have developed a fiber-optics surface-light-scattering spectrometer completely designed with optical fiber components. To the best of our knowledge, this is the first demonstration of a noninvasive measurement of the surface tension and the viscosity of simple liquid-vapor interfaces with a fiber-optics-based sensor system. With this approach we obtain a compact size, a significant increase in the signal-to-noise ratio, and the ability to select from a continuum of wave vectors. (C) 1997 Optical Society of America.Padetha Tin et al.Mon, 20 Oct 1997 07:00:00 +0000https://works.bepress.com/thomas_taylor/2/ArticlesMultiple-Scattering Suppression by Cross Correlationhttps://works.bepress.com/thomas_taylor/4/We describe a new method for characterizing particles in turbid media by cross correlating the scattered intensity fluctuations at two nearby points in the far field. The cross-correlation function selectively emphasizes single scattering over multiple scattering. The usual dynamic light-scattering capability of inferring particle size from decay rate is thus extended to samples that are so turbid as to be visually opaque. The method relies on single-scattering speckle being physically larger than multiple-scattering speckle. With a suitable optical geometry to select nearby points in the far field or equivalently slightly different scattering wave vectors (of the same magnitude), the multiple-scattering contribution to the cross-correlation function may be reduced and in some cases rendered insignificant. Experimental results demonstrating the feasibility of this approach are presented. (C) 1997 Optical Society of America.Mon, 20 Oct 1997 07:00:00 +0000https://works.bepress.com/thomas_taylor/4/ArticlesScaling Dynamics of Aerosol Coagulationhttps://works.bepress.com/thomas_taylor/1/A combination of static and quasielastic light scattering and the theory of scaling solutions to Smoluchowski's equation was used to determine the absolute coagulation rate K'0 and kernel homogeneity lambda of a coagulating liquid-drop aerosol. Droplet sizes ranged from 0.23 to 0.42-mu-m, implying Knudsen numbers in the range 0.26 and 0.14. The temporal evolution of the number concentration M0 and the modal radius r(M) of an assumed zeroth-order log-normal distribution showed near-power-law behavior similar to that predicted by the scaling theory. From the temporal scaling behavior of M0(t) and r(M)(t), the absolute coagulation rate was calculated. The coagulation rates from each method were in good agreement. The rate also agreed well with theory that corrected the Brownian rate, good for the continuum regime, by the average Cunningham correction factor. In addition, the time dependence of the moments M0 and r(M), hence the determination of K'0, was in good agreement with a real-time numerical solution of Smoluchowski's equation for initial conditions analogous to our experimental ones.Wed, 01 Apr 1992 08:00:00 +0000https://works.bepress.com/thomas_taylor/1/ArticlesMoment Analysis of the Cluster-Size-Distribution Approach to Scaling During Coagulationhttps://works.bepress.com/thomas_taylor/5/We study the temporal approach of a cluster size distribution to its asymptotic scaling form. By enforcing consistency between the distribution’s zeroth moment derived from both the Smoluchowski equation and the scaling distribution ansatz, we find values for the scaling exponents w and z in terms of the scaling exponent τ and the kernel homogeneity λ which are not equivalent to their asymptotic, scaling forms. The predicted values do agree well, however, with intermediate time values found in simulations by Kang, Redner, Meakin, and Leyvraz [Phys Rev. A 33, 1171 (1986)]. By enforcing consistency between all moment orders, the asymptotic exponent values are found. These results imply the lowest-order moments approach their scaling values quickest.Thomas W. Taylor et al.Tue, 01 Dec 1987 08:00:00 +0000https://works.bepress.com/thomas_taylor/5/Articles