Size distribution analysis of polymer latex systems by use of the extrema in the angular light scattering pattern. III. Unpolarized and horizontally polarized scattered light

1972 ◽  
Vol 10 (3) ◽  
pp. 527-539 ◽  
Author(s):  
Thomas P. Wallace ◽  
Wayne B. Scott
Keyword(s):  
Light Scattering ◽  
Size Distribution ◽  
Scattered Light ◽  
Distribution Analysis ◽  
Scattering Pattern ◽  
Polymer Latex

scholarly journals Optimum Angles for Multi-Angle Elastic Light Scattering Experiments

2011 ◽  
Author(s):  
D. W. Burr ◽  
K. J. Daun ◽  
K. A. Thomson ◽  
G. J. Smallwood
Keyword(s):  
Inverse Problem ◽  
Light Scattering ◽  
Light Intensity ◽  
Size Distribution ◽  
Design Of Experiment ◽  
Scattered Light ◽  
Scattered Light Intensity ◽  
Elastic Light Scattering ◽  
Optimal Angle ◽  
Ill Posed

In multiangle elastic light scattering (MAELS) experiments, the morphology of aerosolized particles is inferred by shining collimated radiation through the aerosol and then measuring the scattered light intensity over a set of angles. In the case of soot-laden aerosols MAELS can be used to recover, among other things, the size distribution of soot aggregates. This involves solving an ill-posed set of equations, however. While previous work focused on regularizing the inverse problem using Bayesian priors, this paper presents a design-of-experiment methodology for identifying the set of measurement angles that minimizes its ill-posedness. The inverse problem produced by the optimal angle set requires less regularization and is less sensitive to noise, compared with two other measurement angle sets commonly used to carry out MAELS experiments.

scholarly journals SPECTROSCOPIC METHOD FOR EVALUATING THE QUALITY OF A SOLVENT IN GEL-FORMING FIBERS

2021 ◽  
pp. 87-93
Author(s):  
Алена Игорьевна Маркова ◽  
Александр Викторович Соколов ◽  
Светлана Дмитриевна Хижняк ◽  
Павел Михайлович Пахомов
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Size Distribution ◽  
Optical Spectroscopy ◽  
Scattered Light ◽  
Spectroscopic Method ◽  
Average Size ◽  
Ultra High Molecular Weight

Предложен метод оптической спектроскопии для оценки качества растворителя, на примере вазелинового масла (ВМ), используемого при гель-формованиии сверхвысокомолекулярного полиэтилена (СВМПЭ). Метод основан на анализе упруго рассеянного света от частиц загрязнителя в ВМ. С помощью этого метода удалось определить средний размер рассеивающих частиц и их распределение по размерам. Методы динамического светорассеяния (ДСР) и оптической микроскопии подтвердили данные о среднем размере частиц загрязнителя в ВМ и их распределении по размерам, полученные методом оптической спектроскопии. A method of optical spectroscopy for evaluating the quality of a solvent is proposed, using the example of vaseline oil (VM) used in gel molding of ultra-high molecular weight polyethylene (UHMWPE). The method is based on the analysis of elastically scattered light from pollutant particles in a VM. Using this method, it was possible to determine the average size of scattering particles and their size distribution. The methods of dynamic light scattering (DLS) and optical microscopy have confirmed the data on the average size of pollutant particles in VM and their size distribution obtained by optical spectroscopy.

Self-Assembly Of Fibrin Monomers Measured By Quasielastic Light-Scattering

1981 ◽  
Author(s):  
D E Guinnup ◽  
J S Schultz
Keyword(s):  
Light Scattering ◽  
Size Distribution ◽  
Self Assembly ◽  
Scattered Light ◽  
Monomer Concentration ◽  
Radius Of Gyration ◽  
Published Data ◽  
Minute Period ◽  
In Situ Experiments

Purified fibrin monomer solutions were prepared in 1 M sodium bromide by alternation of precipitation and solubilization with pH adjustments between 6.0 and 5.3. The final preparation, at pH 5.3, was checked for monodispersity and purity by quasielastic laser light-scattering and was found to have a translational diffusion coefficient of 2.14 × 10-7 cm2/sec and a radius of gyration of 286 A, in excellent agreement with published data.The kinetics of fibrin self-assembly was monitored in-situ by measuring the autocorrelation function and mean intensity of scattered light with time after abruptly changing the pH froft 5.0 to 6.3 in 1 M NaBr. The data were most consistent with an assembly model wherein fibrin associated with itself in an overlapping staggered end to end configuration. The evolving particle size distribution of fibrin fibrils was obtained by deconvoluting the autocorrelation functions obtained over a 30 minute period and unexpectedly revealed that larger aggregates, containing greater than about 6 fibrin units, were greatly favored over smaller aggregates, dimers, trimers, etc. Also, while the rate of fibrin assembly appeared to be proportional to the square of the monomer concentration, consistent with simple aggregation theory, the probability of a collision between particles resulting in the growth of a fibril was very small.Additional in-situ experiments under laminar shear conditions in the physiological range showed the same pattern of fibril size distribution, except that the rate of self-assembly decreased about 30% as shear increased to 1000 sec-1.

scholarly journals Evaluating the PurpleAir monitor as an aerosol light scattering instrument

2021 ◽  
Author(s):  
James R. Ouimette ◽  
William C. Malm ◽  
Bret A. Schichtel ◽  
Patrick J. Sheridan ◽  
Elisabeth Andrews ◽  
...  
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Size Distribution ◽  
Field Data ◽  
Scattered Light ◽  
Concentration Field ◽  
Scattering Coefficient ◽  
Coefficient Of Determination ◽  
Aerosol Size Distribution ◽  
Aerosol Mass Concentration

Abstract. The Plantower PMS5003 sensors (PA-PMS) used in the PurpleAir (PA) monitor PA-II-SD configuration are equivalent to cell-reciprocal nephelometers using a 657 nm perpendicularly polarized light source that integrates light scattering from 18 to 166 degrees. Yearlong field data at the National Oceanic and Atmospheric Administration’s (NOAA) Mauna Loa Observatory (MLO) and Boulder Table Mountain (BOS) sites show that the 1 h average of the PA-PMS first size channel, labeled “> 0.3 μm” (“CH1”) is highly correlated with submicrometer aerosol scattering coefficients at the 550 nm and 700 nm wavelengths measured by the TSI 3563 integrating nephelometer, from 0.4 Mm−1 to 500 Mm−1. This corresponds to an hourly average submicrometer aerosol mass concentration of approximately 0.2 to 200 ug m−3. A physical-optical model of the PA-PMS is developed to estimate light intensity on the photodiode, accounting for angular truncation as a function of particle size. Predictions are then compared with yearlong fine aerosol size distribution and scattering coefficient field data at the BOS site. It is shown that CH1 is linearly proportional to the model-predicted intensity of the light scattered by particles in the PA-PMS laser to its photodiode over 4 orders of magnitude. This is consistent with CH1 being a measure of the scattering coefficient and not the particle number concentration or particulate matter concentration. Field data at BOS confirm the model prediction that the ratio of CH1 to the scattering coefficient would be highest for aerosols with median scattering diameters < 0.3 μm. The PA-PMS detects aerosols smaller than 0.3 μm diameter in proportion to their contribution to the scattering coefficient. The model predicts that the PA-PMS response to particles > 0.3 μm decreases relative to an ideal nephelometer by about 75 % for particle diameters ≥ 1.0 μm. This is a result of using a laser that is polarized, the angular truncation of the scattered light, and particle loss in the instrument before reaching the laser. The results of this study indicate that the PA-PMS is not an optical particle counter and that its six size fractions are not an accurate representation of particle size distribution. The relationship between the PA-PMS 1 h average CH1 and bsp1, the scattering coefficient in Mm−1 due to particles below 1 μm aerodynamic diameter, at wavelength 550 nanometers, is found to be bsp1 = 0.015 ± 2.07 × 10−5 × CH1, for relative humidity below 40 %. The coefficient of determination R2 is 0.97. This suggests that the low-cost and widely used PA monitors can be used to measure and predict the aerosol light scattering coefficient in the mid-visible nearly as well as integrating nephelometers.

Influence of the Angular Light Scattering Measurement Uncertainly on the Particle-Size Distribution

2007 ◽  
Vol 121-123 ◽  
pp. 909-912
Author(s):  
J.A. Martínez ◽  
M.P. Hernández
Keyword(s):  
Particle Size ◽  
Standard Deviation ◽  
Light Scattering ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Scattered Light ◽  
Colloidal Suspension ◽  
Size Distribution Function ◽  
Scattered Intensity ◽  
Static Approach

The determination of the spherical particle-sizes in colloidal suspension by Angular Light Scattering presents a lot of advantages, i.e.: the relative simplicity of the experimental installations, and its non-destructive character. The intensity of the scattered light is related with the radius of a particle by Mie Theory. However, the dynamic characteristic of the measurements establish a variations of the scattered intensity with the time which it has not considered. In the case of the particle suspended in water, the intensity of the scattered light measured in each angle θ is the superposition of the scattered intensity for each particle. In consequence, the intensity of the light scattered will be related with a particle-size distribution function, that in this work is assumed as a δ function. Then, the dependence of the scattered intensity with time is studied evaluating the variation of the center point of δ function with time taking account to the standard deviation of angular scattered intensity. The accuracy of the method is evaluated throw the deviation of the particle-size distribution taking in to account the standard deviation of the angular intensity scattered by calibrated particles of latex. A correct evaluation of the dynamic method is realized in terms of the static approach.

Sign in / Sign up

Export Citation Format

Share Document