A method and system for gauging deviations of a surface of a test part from a preselected nominal surface profile is disclosed. The system includes a support having a master surface that is substantially a matched or mating surface of the nominal surface profile of the test part and a thin layer of an attenuating medium such as a dye liquid between the master and test surfaces. Electromagnetic radiation is directed through the support and master surface and through the attenuating layer onto the reflective surface of the test part. An image sensor such as a camera is positioned to receive an image of the radiation reflected by the test part surface back through the attenuating layer and support, with the intensity of such radiation across the image varying as a function of the deviation of the test part surface from the nominal surface profile. The sensor output is digitized to form a series of digital signals indicative of the intensity of radiation associated with each location of the reflected image, and the digitized pixel signals are stored in digital electronic memory and/or displayed on a screen. Computer programming corrects the digitized intensity signals for sensor gain, bias and variations in part reflectivity, and presents a quantitative measurement of the deviations in test surface profile from the master surface profile over the entire surface being measured.

An elongated, generally vertically extending reactor vessel for the production of hypochlorous acid by the mixing and reaction of a liquid alkali metal hydroxide and a gaseous halogen is provided with solids discharge handling apparatus connected to the bottom to remove the solid by-product. The discharge handling apparatus uses the solids to effect a seal to prevent the intrusion of outside air into the reactor and the escape of halogen and product gas to the outside atmosphere.

The disclosure is directed to a process and apparatus for isoelectric focusing and isotachophoresis of fluids. Recycling of the process fluid is established in a first direction through an electrophoretic chamber having parallel walls, the electric field being applied in a second direction. Externally of the chamber, the flow of fluid is subdivided into a plurality of closed loops, cooled to dissipate the Joule heat. While maintaining conditions of laminar flow within the chamber, unusual fluid stabilization against convective, electroosmotic and other fluid flow disturbances is obtained if the gap between the parallel walls of the chamber is kept narrow and the fluid flow is rapid, to maximize shear stress at the walls of the chamber and minimize the fluid residence time in the chamber.

Apparatus for the separation of a solid salt by-product from the product gaseous hypohalogenated acid of a reactor is disclosed which is effective to separate particles ranging in size from about 0.5 to about 50 microns. The reactor mixes an aqueous alkali metal hydroxide and a gaseous halogen to produce the hypohalogenated acid product and solid salt by-product which are discharged from the reactor into the separation apparatus.