This year project of the spherical reference materials is to manufacture both transparent (LBP 150-650) and opaque (GCP 150-650) particles having unimodal size distribution in the range of 150 to 650pm.
1) The transparent particles are soda-lime-silicate glass beads denoted by LBP150-650, and more than 95% in weight of these particles are in the size range of 150 to 650pm. The product materials, LBP150-650, of 30kg were sent to the AEA Technology, England for the certification in December, 1993.
2) The opaque particles are glassy carbon beads denoted by GCPlSO- 650, and more than 95% in weight of these particles are in the size range of 150 to 650 pm. The product materials, GCP150-650, of 24kg were also sent to the AEA Technology, England in May, 1994.
The physical characteristics of the above product materials, especially the size distributions, were measured in several Japanese company- laboratories, and are given in this report.
We also studied the size segregation of larger particles in a vessel through tapping, resulting in a significant segregation. Therefore, complete mixing and/or careful splitting is necessary before utilizing them as the reference materials.
The next year project will be concerned with the following two problems relating the standard materials.
A. to get additional important physical properties of the standard materials.
B. to find a method for estimating the statistical error caused by the sample size utilized in a particle size measurement.