Forward light scattering to characterise structure of flocs composed of large particles

2005 ◽  
Vol 111 (2-3) ◽  
pp. 145-149 ◽  
Author(s):  
Graeme Bushell
Keyword(s):  
Light Scattering ◽  
Large Particles

Light Scattering by Large Particles

1986 ◽  
Vol 33 (8) ◽  
pp. 1001-1022 ◽  
Author(s):  
Jean-Marie Perrin ◽  
Philippe L. Lamy
Keyword(s):  
Light Scattering ◽  
Large Particles

Angle-dependent effects in Dynamic Light Scattering measurements of polydisperse particles

2021 ◽  
Author(s):  
Lin Jin ◽  
Curtis W Jarand ◽  
Mark L Brader ◽  
Wayne F Reed
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Laser Wavelength ◽  
Recent Emergence ◽  
Large Particles ◽  
Average Diffusion ◽  
Biological Polymers ◽  
Average Size ◽  
The Relationship

Abstract Dynamic light scattering (DLS) is widely used for analyzing biological polymers and colloids. Its application to nanoparticles in medicine is becoming increasingly important with the recent emergence of prominent lipid nanoparticle-(LNP)based products, such as the SARS-CoV-2 vaccines from Pfizer, Inc.-BioNTech (BNT162b2) and Moderna, Inc. (mRNA-1273). DLS plays an important role in the characterization and quality control of nanoparticle-based therapeutics and vaccines. However, most DLS instruments have a single detection angle ,and the amplitude of the scattering vector, q, varies among them according to the relationship q=(n/sin(/2) where 0 is the laser wavelength. Results for identical, polydisperse samples among instruments of varying q yield different hydrodynamic diameters, because, as particles become larger they scatter less light at higher angles, so that higher-q instruments will under-sample large particles in polydisperse populations, and report higher z-average diffusion coefficients, and hence smaller effective hydrodynamic diameters than lower-q instruments. As particle size reaches the Mie regime the scattering envelope manifests angular maxima and minima, and the monotonic decrease of average size versus q is lost. This work examines results for different q-value instruments, using mixtures of monodisperse latex sphere standards, for which experimental measurements agree well with computations, and also polydisperse solutions of LNP, for which results follow expected trends. Mie effects on broad unimodal populations are also considered. There is no way to predict results between two instruments with different q for samples of unknown particle size distributions.

Improving the Sensitivity of Forward Light Scattering Technique to Large Particles

1999 ◽  
Vol 16 (2) ◽  
pp. 71-76 ◽  
Author(s):  
Zhenhua Ma ◽  
Henk G. Merkus ◽  
Jan G. A. E. de Smet ◽  
Peter J. T. Verheijen ◽  
Brian Scarlett
Keyword(s):  
Light Scattering ◽  
Large Particles ◽  
Scattering Technique ◽  
Light Scattering Technique

scholarly journals ANGULAR LIGHT-SCATTERING STUDIES ON ISOLATED MITOCHONDRIA

1961 ◽  
Vol 10 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Gerald S. Gotterer ◽  
Thomas E. Thompson ◽  
Albert L. Lehninger
Keyword(s):  
Light Scattering ◽  
Optical Density ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Density Measurements ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Large Particles ◽  
Scattering Measurements ◽  
Increased Sensitivity

Angular light-scattering studies have been carried out on suspensions of isolated rat liver mitochondria. The angular scatter pattern has a large forward component, typical of large particles. Changes in dissymmetry and in the intensity of light scattered at 90° have been correlated with changes in optical density during the course of mitochondrial swelling and contraction. Such changes can be measured at mitochondrial concentrations much below those required for optical density measurements. Changes in mitochondrial geometry caused by factors "leaking" from mitochondria, not detectable by optical density measurements, have been demonstrated by measuring changes in dissymmetry. Angular light-scattering measurements therefore offer the advantages of increased sensitivity and of added indices of changes in mitochondrial conformation.

scholarly journals A new method for calculating number concentrations of cloud condensation nuclei based on measurements of a three-wavelength humidified nephelometer system

2018 ◽  
Vol 11 (2) ◽  
pp. 895-906 ◽  
Author(s):  
Jiangchuan Tao ◽  
Chunsheng Zhao ◽  
Ye Kuang ◽  
Gang Zhao ◽  
Chuanyang Shen ◽  
...  
Keyword(s):  
Light Scattering ◽  
Cloud Condensation Nuclei ◽  
Number Concentration ◽  
New Method ◽  
Lookup Table ◽  
Ambient Atmosphere ◽  
Condensation Nuclei ◽  
The North ◽  
Direct Measurements ◽  
Large Particles

Abstract. The number concentration of cloud condensation nuclei (CCN) plays a fundamental role in cloud physics. Instrumentations of direct measurements of CCN number concentration (NCCN) based on chamber technology are complex and costly; thus a simple way for measuring NCCN is needed. In this study, a new method for NCCN calculation based on measurements of a three-wavelength humidified nephelometer system is proposed. A three-wavelength humidified nephelometer system can measure the aerosol light-scattering coefficient (σsp) at three wavelengths and the light-scattering enhancement factor (fRH). The Ångström exponent (Å) inferred from σsp at three wavelengths provides information on mean predominate aerosol size, and hygroscopicity parameter (κ) can be calculated from the combination of fRH and Å. Given this, a lookup table that includes σsp, κ and Å is established to predict NCCN. Due to the precondition for the application, this new method is not suitable for externally mixed particles, large particles (e.g., dust and sea salt) or fresh aerosol particles. This method is validated with direct measurements of NCCN using a CCN counter on the North China Plain. Results show that relative deviations between calculated NCCN and measured NCCN are within 30 % and confirm the robustness of this method. This method enables simplerNCCN measurements because the humidified nephelometer system is easily operated and stable. Compared with the method using a CCN counter, another advantage of this newly proposed method is that it can obtain NCCN at lower supersaturations in the ambient atmosphere.

scholarly journals Homogeneous Nucleation of Hydroxyapatite, Ca5OH(PO4)3, at 37 °C

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 695 ◽  
Author(s):  
Hans Erik Lundager Madsen
Keyword(s):  
Free Energy ◽  
Light Scattering ◽  
Calcium Phosphate ◽  
Surface Free Energy ◽  
Classical Theory ◽  
Homogeneous Nucleation ◽  
Crystal Surface ◽  
Small Particles ◽  
Large Particles

Precipitation of the calcium phosphate hydroxyapatite, Ca5OH(PO4)3, is studied by simple mixing of reagent solutions and measurement of light scattering (turbidimetry) at six different wavelengths from 300 to 800 nm. Measured turbidities are analyzed using Mie’s theory of light scattering from small particles. Results are interpreted in terms of classical theory of homogeneous nucleation, and from this the surface free energy of crystals is determined. The low value thus found is explained as the effect of protonation of the strongly basic anions hydroxide and phosphate at the crystal surface. Relatively large particles registered by turbidimetry are shown to be not monocrystals, but aggregates of nanocrystals.

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