Phenol exists in wastewater streams for many industrial processes. The toxicity of phenolic effluents is well known and their treatment must be accomplished. Among the methods of recovery, the technique of adsorption provides a convenient way with low cost. For modelling the diffusion process it is necessary to know the diffusion constant. The technique of double-exposure holographic interferometry (HI) is used to study phenol diffusion in water in the presence and in the absence of activated carbon. The diffusion constant is calculated by a simple and direct measurement of interferograms.

A method for local thermodynamic equilibrium plasma diagnostics by vibrational structure of diatomic molecule electronic states is elaborated. On this purpose is adopted a model of plasma temperature determination from the relative intensities of the molecular vibrational band head incompletely spectrally resolved. The relative intensities were determined using the temporal integrated profile instead of peak or integrated spectral profile of a band head. This more accurate method of vibrational temperature determination allows obtained new data about the plasma internal processes.

Sedimentation of the suspension process is important, especially in pollution, biologic liquids or polymers studies.Unlike the usual methods, as those using pipettes, areometer or balances', the optical ones are nondestructive and more accurate.During sedimentation produced by the braked fall of the solid particles in suspension, fluctuations produced by an opposite vertical diffusion occur; this process is lost using the chemical methods, which weigh the mass fallen on a submersed plate.We used a scattering method, based on the attenuation of a laser beam which, in the absence of absorption, describes the variation of solid particles' concentration in the suspension.

Interfacial turbulence is investigated experimentally by microscope observations and holographic interferometry with double exposure for the system glycerol-acetic acid-n-butyl- acetate. This system exhibits organized interfacial activity upon transfer of acetic acid from glycerol phase to acetate phase. This behavior was confirmed by the microscope observations in transmitted light. For the holograms obtained the deviation of the fringes between the two exposure times can be related with the changes in the concentration profiles near the interface. Because of the complexity of the phenomenon investigated, the present study is only qualitatively.

Under the action of external factors, the dimensions, as well as many internal properties, of bodies change; using holographic interferometry, even very small changes of this kind can be studied. Holographic stress analysis allows one to establish the internal distribution of the stress in the medium, produced by external forces. Transparent samples, in which the stress produces a distribution of the refractive index, are usually used. However, the deformations induced by external forces are able, in some cases, to reveal the internal modifications in nontransparent bodies. Mechanical deformations of some nonhomogeneous solid media (as concrete used in construction), are not accurately elastic. We present a holographic nondestructive method for studying the deformations of bars made of concrete, which are connected with some internal properties of the solid bars, such as the modulus of elasticity. The results we obtained reveal some deviations from the elastic deformation model. (C) 1996 Society of Photo-Optical Instrumentation Engineers.