A quantitative image analysis method for characterizing mixtures of granular materials

Abstract Automated image analysis is used to characterize the structure of undisturbed granular mixtures. These mixtures, produced from small-scale mixing experiments, are preserved using solidification techniques, sliced, and scanned using a video camera to produce a digital image. Image analysis is used to determine the mean, mode, standard deviation, variance, and skewness of local composition for a large number of locations in the mixtures, providing an effective method for performing a detailed quantitative characterization of the mixture structure. The digital data are then used to simulate random sampling from a powder blender. Sampling parameters, such as number of samples, sample size, and location of the samples, are varied to assess their effect on the descriptive statistics. For partially mixed systems such as those examined here, results depend strongly on the number of samples used in the analysis, but they are largely independent of sample size. The solidification techniques, image analysis methods, and numerical algorithms for quantifying features of the partially mixed structures are described in detail.

[1]  N. Harnby,et al.  A comparison of the performance of industrial solids mixers using segregating materials , 1967 .

[2]  N. Harnby.  Chapter 2 – Characterization of powder mixtures , 1992 .

[3]  Douglas W. Fuerstenau,et al.  Diffusional mixing in an ideal system , 1966 .

[4]  F. Muzzio,et al.  The structure of mixtures of particles generated by time-dependent flows , 1995 .

[5]  J. A. Hersey,et al.  The variance-sample size relationship and the effects of magnesium stearate on ordered powder mixtures , 1981 .

[6]  H. Kristensen.  The characterization of non-random mixtures. A survey , 1975 .

[7]  Suresh K. Bhatia,et al.  Axial transport of granular solids in rotating cylinders. Part 2: Experiments in a non-flow system , 1991 .

[8]  Leonard G. Austin,et al.  Axial mixing of particles in batch ball mills , 1973 .

[9]  N. Pilpel,et al.  Effect of Particle Shape on the Mixing of Powders , 1990, The Journal of pharmacy and pharmacology.

[10]  P. Stephenson,et al.  Assessing the homogeneity of an ordered mixture , 1982 .

[11]  I. Inoue,et al.  Mixing of solid particles of different density in a horizontal batch mixer. Measurement of axial diffusion coefficients , 1980 .

[12]  The effect of mixing aids on the kinetics of mixing in a rotating drum , 1971 .

[13]  Z. Chowhan,et al.  Mixing of pharmaceutical solids. IV. Effects of concentration and material properties on multicomponent mixing of cohesive powders , 1981 .

[14]  P. V. Danckwerts.  The Definition and Measurement of Some Characteristics of Mixtures , 1952 .

[15]  K. Miyanami,et al.  Influence of rocking motion on the mixing of powders , 1989 .

[16]  J. A. Hersey,et al.  Perfect powder mixtures , 1977 .

[17]  M. B. Donald,et al.  The mixing of solids in tumbling mixers—I , 1962 .

[18]  R. Shinnar,et al.  An experimental study of intimate mixing of solid particles , 1963 .

[19]  S. Masiuk,et al.  Power consumption, mixing time and attrition action for solid mixing in a ribbon mixer , 1987 .

[20]  M. F. Edwards,et al.  Mixing in the process industries , 1985 .

[21]  P. Stewart,et al.  Mixing and demixing of microdose quantities of sodium salicylate in a direct compression vehicle , 1979 .

[22]  Jay L. Devore,et al.  Probability and statistics for engineering and the sciences , 1982 .

[23]  Studies on the diffusion and mixing of solid particles in a tube mixer—V. Practical studies on a binary system with two radioactivated components , 1973 .

[24]  J. C. Williams,et al.  The properties of non-random mixtures of solid particles , 1969 .