Particle size distributions from small-angle scattering using global scattering functions

2004 ◽  
Vol 37 (4) ◽  
pp. 523-535 ◽  
Author(s):  
G. Beaucage ◽  
H. K. Kammler ◽  
S. E. Pratsinis

Control and quantification of particle size distribution is of importance in the application of nanoscale particles. For this reason, polydispersity in particle size has been the focus of many simulations of particle growth, especially for nanoparticles synthesized from aerosols such as fumed silica, titania and alumina. Single-source aerosols typically result in close to a log-normal distribution in size and micrograph evidence generally supports close to spherical particles, making such particles ideal candidates for considerations of polydispersity. Small-angle X-ray scattering (SAXS) is often used to measure particle size in terms of the radius of gyration,Rg, using Guinier's law, as well as particle surface area,S/V, from the Porod constantBand the scattering invariantQ. In this paper, the unified function is used to obtain these parameters and various moments of the particle size distribution are calculated. The particle size obtained from BET analysis of gas adsorption data directly agrees with the moment calculated fromS/V. Scattering results are also compared with TEM particle-counting results. The potential of scattering to distinguish between polydisperse single particles and polydisperse particles in aggregates is presented. A generalized index of polydispersity for symmetric particles, PDI =BRg4/(1.62G), whereGis the Guinier prefactor, is introduced and compared with other approaches to describe particle size distributions in SAXS, specifically the maximum-entropy method.

1984 ◽  
Vol 143 ◽  
pp. 387-411 ◽  
Author(s):  
I. A. Valioulis ◽  
E. J. List ◽  
H. J. Pearson

Hunt (1982) and Friedlander (1960a, b) used dimensional analysis to derive expressions for the steady-state particle-size distribution in aerosols and hydrosols. Their results were supported by the Monte Carlo simulation of a non-interacting coagulating population of suspended spherical particles developed by Pearson, Valioulis & List (1984). Here the realism of the Monte Carlo simulation is improved by accounting for the modification to the coagulation rate caused by van der Waals', electrostatic and hydrodynamic forces acting between particles. The results indicate that the major hypothesis underlying the dimensional reasoning, that is, collisions between particles of similar size are most important in determining the shape of the particle size distribution, is valid only for shear-induced coagulation. It is shown that dimensional analysis cannot, in general, be used to predict equilibrium particle-size distributions, mainly because of the strong dependence of the interparticle force on the absolute and relative size of the interacting particles.


1968 ◽  
Vol 12 ◽  
pp. 87-96
Author(s):  
R. W. Gould ◽  
S. R. Bates

AbstractIt has been recently shown that particle size distributions can be determined from small angle x-ray scattering data. Size distributions have previously been measured in aluminum-zinc and aluminum-silver alloys containing spherical Guinier-Preston zones. Inorder to obtain the size distribution it is only necessary to calculate the Guinier radius and the Porod radius.Dispersion hardened nickel alloys containing small spherical particles of thoria appear to be amenable to this type of analysis. A nickel-20% chromium-2% ThO2 alloy was selected for this study. The particle size distribution obtained by small angle x-ray scattering is compared with the transmission electron microscopy results found in the literature.


2010 ◽  
Vol 177 ◽  
pp. 22-24
Author(s):  
Zheng Min Li ◽  
Zhi Wei Chen ◽  
Min Tan ◽  
Ke Jing Xu ◽  
Bing Jiang

Nano-TiO2 coating film is one of the efficient photocatalysts. The particle size distribution of TiO2 has important influence on photocatalytic activity. A new method to determine the particle size distribution of TiO2 nano-film coated on ceramic was developed, by which the images of film acquired by Atom force microscope (AFM) were processed, and TiO2 particles contacted with others were separated and detected. The particle size distributions of two TiO2 nano-films were determined.


1994 ◽  
Vol 74 (2) ◽  
pp. 383-385 ◽  
Author(s):  
R. Soofi-Siawash ◽  
G. W. Mathison

Two studies were conducted to assess the possibility of using particle size distribution following grinding as a routine procedure of forage evaluation. It was concluded that although differences in particle size distribution could be detected when different feeds were ground, it would be difficult to standardize the technique since particle size distributions were influenced by type of mill used for grinding, particle size of forage before grinding, and moisture content of the forage. Key words: Forages, grinding, particle size, moisture, mill


2020 ◽  
Vol 57 (11) ◽  
pp. 1684-1694
Author(s):  
Shijin Li ◽  
Adrian R. Russell ◽  
David Muir Wood

Internal erosion (suffusion) is caused by water seeping through the matrix of coarse soil and progressively transporting out fine particles. The mechanical strength and stress–strain behavior of soils within water-retaining structures may be affected by internal erosion. Some researchers have set out to conduct triaxial erosion tests to study the mechanical consequences of erosion. Prior to conducting a triaxial test they subject a soil sample, which has an initially homogeneous particle-size distribution and density throughout, to erosion by causing water to enter one end of a sample and wash fine particles out the other. The erosion and movement of particles causes heterogeneous particle-size distributions to develop along the sample length. In this paper, a new soil sample formation procedure is presented that results in homogeneous particle-size distributions along the length of an eroded sample. Triaxial tests are conducted on homogeneous samples formed using the new procedure as well as heterogeneous samples created by the more commonly used approach. Results show that samples with homogeneous post-erosion particle-size distributions exhibit slightly higher peak deviator stresses than those that were heterogeneous. The results highlight the importance of ensuring homogeneity of post-erosion particle-size distributions when assessing the mechanical consequences of erosion. Forming samples using the new procedure enables the sample’s response to triaxial loading to be interpreted against a measure of its initially homogenous state.


CrystEngComm ◽  
2018 ◽  
Vol 20 (38) ◽  
pp. 5672-5676 ◽  
Author(s):  
Run-Zhi Zhang ◽  
Yong-qing Huang ◽  
Wei Zhang ◽  
Ji-Min Yang

UiO-67 nano/microcrystals with different particle size distributions (PSDs) were successfully obtained by a simple solvothermal method.


2017 ◽  
Vol 898 ◽  
pp. 1717-1723 ◽  
Author(s):  
Xue Mei Yi ◽  
Shota Suzuki ◽  
Xiong Zhang Liu ◽  
Ran Guo ◽  
Tomohiro Akiyama

Combustion synthesis (CS) of β-SiAlON was conducted using a 3D ball mill, with a focus on the effect of the 2D/3D ball mill premixing conditions on the CS raw material particle size as well as on the yield and grain shape of the final products. The results showed that the particle size distribution of the raw materials was significantly affected by the premixing conditions. Various particle sizes and particle size distributions could easily be obtained by using a 3D mill instead of a 2D mill due to the complex biaxial rotation movement of 3D milling. The particle size was more sensitive to the rotation ratio (vertical spin/horizontal spin, Vv/Vh) than the rotation rate when using 3D milling. Finally, β-SiAlON with less than 5 mass% unreacted Si was obtained using premix milling conditions of 135×200 [vertical spin (rpm) × horizontal spin (rpm)]. The grain shapes of the final products were clearly influenced by the particle size distribution of the raw mixtures.


2019 ◽  
Vol 34 (7) ◽  
pp. 1380-1386 ◽  
Author(s):  
Guillaume Bucher ◽  
François Auger

Particle size distribution (PSD) of a highly polydisperse TiO2 sample determined by spICP-MS.


Clay Minerals ◽  
1997 ◽  
Vol 32 (1) ◽  
pp. 3-11 ◽  
Author(s):  
M. Arias ◽  
E. Lopez ◽  
M. T. Barral

AbstractAlthough it is generally agreed that Fe and Al can act to bind soil particles, their relative efficiencies as aggregants are still disputed. In this work, the aggregating efficiencies of both aged and non-aged Fe and Al oxides precipitated on kaolin or quartz substrates were characterized by comparing their effects on particle size distributions (PSD). To facilitate comparison of PSD data, these were parameterized by fitting them with five different probability density functions (the normal, lognormal, Jaky, fractal and Rosin-Rammler functions). The best fits were given by the Rosin-Rammler function (R2 = 0.997), whose α parameter was used to compare the aggregating efficiency of Fe and Al oxides: in order of decreasing efficiency, non-aged Al > non-aged Fe ≈ aged Fe > aged Al-precipitates.


2010 ◽  
Vol 10 (16) ◽  
pp. 8065-8076 ◽  
Author(s):  
S. Hosseini ◽  
Q. Li ◽  
D. Cocker ◽  
D. Weise ◽  
A. Miller ◽  
...  

Abstract. Particle size distribution from biomass combustion is an important parameter as it affects air quality, climate modelling and health effects. To date, particle size distributions reported from prior studies vary not only due to difference in fuels but also difference in experimental conditions. This study aims to report characteristics of particle size distributions in well controlled repeatable lab scale biomass fires for southwestern United States fuels with focus on chaparral. The combustion laboratory at the United States Department of Agriculture-Forest Service's Fire Science Laboratory (USDA-FSL), Missoula, MT provided a repeatable combustion and dilution environment ideal for measurements. For a variety of fuels tested the major mode of particle size distribution was in the range of 29 to 52 nm, which is attributable to dilution of the fresh smoke. Comparing mass size distribution from FMPS and APS measurement 51–68% of particle mass was attributable to the particles ranging from 0.5 to 10 μm for PM10. Geometric mean diameter rapidly increased during flaming and gradually decreased during mixed and smoldering phase combustion. Most fuels produced a unimodal distribution during flaming phase and strong biomodal distribution during smoldering phase. The mode of combustion (flaming, mixed and smoldering) could be better distinguished using the slopes in MCE (Modified Combustion Efficiency) vs. geometric mean diameter than only using MCE values.


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