Measurement of gradient index profiles by Babinet fringe analysis.
A theory for determining one-dimensional ray deflections with the help of distorted Babinet fringes has been developed. An approach for investigating two-dimensional ray deflections has been presented. Applications of the techniques for the study of gradient index glass have been described.
The Formation of Fringes in a Babinet Compensator
Details are given of the appearance of the field of view when two wedges of doubly refracting material are placed in arbitrary azimuths between crossed polarizing devices. In general the field of view presents a complex pattern but simple fringe systems appear for suitable orientation of the wedges, one of which is the well-known Babinet fringe system. Theoretical relationships are derived for the intensity distribution in the general case and for the simple cases. Photographs show how the simple fringe systems are formed out of the complex cases. A use of the patterns for detecting if the wedges of a Babinet compensator are correctly mounted is mentioned.
Intensification of Bubble Disintegration and Dispersion by Mechanical Stirring in Gas Injection Refining
Water model experiments were performed for establishing highly efficient gas injection refining processes. Mechanical stirring was applied to disintegrate the injected bubbles and to disperse them widely in the bath. The bubble disintegration and dispersion were investigated by changing rotation mode (direction of rotation), rotation speed, blade size of the impeller and gas flow rate. Forward rotation of the impeller induced a stable tangential flow and could not disperse bubbles in the bath due to formation of a vortex around the impeller shaft. The tangential flow could be suppressed by forward–interrupt rotation, which could reduce the vortex formation to some degree. However, forward–interrupt rotation could not disperse the bubbles widely in the bath. Forward–reverse rotation could prevent the vortex formation completely and create a strong shear stress field, which intensified the bubble disintegration and dispersion in the bath. Higher impeller rotation speed and larger blade length in forward–reverse rotation could enhance the bubble disintegration and make the dispersed bubbles smaller. The bubble dispersion zone became wider with larger blade length. The bubble size tended to be larger at higher gas flow rates. However, its dependence on the gas flow rate became smaller at higher impeller rotation speed.