A transmissometer was developed to measure dust concentration at stationary sources employing an LED ( Light Emitting Diode) and a self-compensation system for the degradation of the optical system. The relationship between the optical concentration obtained by the tansmissometer and the mass concentration measured by a gravimetric method were investigated theoretically and experimentally.
The experiments were carried out with four kinds of test dusts. Very good correlations between the optical concentration and the mass concentration were obtained over a wide range of dust concentration, about 10mg/m³-5g/m³. It was found that dust concentration can be measured accurately for a long period with this tansmissometer in which the self-compensation system for optical degradation is very effective. A comparison between the experimental values and calculated results showed good agreement between the phenomenon and the theory of light extinction. It was also found that the effect of dust properties, such as the refractive index and the particle size distribution, can be estimated by calculating parameter K.

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To investigate the flow and mixing characteristics of the solid mixer, three sets of the optical fiber probes have been installed in the mixer vessel. The mixer employed in this work was a rotary-cylinder type mixer wth rocking motion using a swinging bed mechanism. The concentration changes with time and the pattern of the mixing curves have been measured by using the tracer particles coated with dye powder. It has been shown that two different mixing rate coefficients φ₁ and φ₂ represent the different mechanisms, i. e, convective and shearing or diffusive mixing. The mixing characteristics of the mixer have been evaluated based on these two kinds of rate coefficients measured under various operating conditions.

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The relationship between the increasing rate of holdup and the feed rate were examined. From the results, the maximum crushing capacity was defined as the maximum feed rate where holdup did not change with time and remained at a constant value.
The effect of the hammer rotation speed, ω, and the reduction ratio, D_v/d_v, on the maximum crushing capacity, F_max, was expressed as follows:
F_max=K₂(D_v/d_v)^-1ω²

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The cascade-forming circulation flow of particles in a horizontal rotary cylinder was first expressed inductively in terms of the characteristics that determine the profiles of the regions organizing circulation flow. This was done with equations expressing the operational condition, that is, the hold up ratio and/or Froude number, making use of data published by other researchers.
Secondly, through those studies, the motion of the particles in each region, and thereby of the entire circulation flow was analyzed. Methods to calculate the position of the whirl core, the retention time of particles in each region, and the theoretical power required for circulation in the rotary cylinder could be calculted.

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