Electrooxidation Using Nb/BDD as Post-Treatment of a Reverse Osmosis Concentrate in the Petrochemical Industry.

This work evaluated the performance of an electrochemical oxidation process (EOP), using boron-doped diamond on niobium substrate (Nb/BDD), for the treatment of a reverse osmosis concentrate (ROC) produced from a petrochemical wastewater. The effects of applied current density (5, 10, or 20 mA·cm) and oxidation time (0 to 5 h) were evaluated following changes in chemical oxygen demand (COD) and total organic carbon (TOC). Current efficiency and specific energy consumption were also evaluated.

Picosecond measurements of absorptive and refractive optical nonlinearities in GaP at 532 nm.

Picosecond time-resolved pump-probe and Z-scan measurements are used to investigate the nonlinear refraction and absorption associated with intense picosecond excitation above the indirect band edge of GaP. The pump-probe results reveal both an instantaneous absorption feature, which is consistent with two-photon absorption, and a long-lived feature that is associated with the generation of free carriers by linear indirect absorption. Z scans conducted with pulses of 25- and 95-ps duration indicate that, for these pulse widths, the nonlinear refraction in GaP is dominated by the linear generation of free carriers and that the role of the electronic Kerr effect is negligible.

Improved space-marching algorithm for strong acousto-optic interaction of arbitrary fields.

We present a modification of the beam-propagation algorithm that avoids computer-intensive processing of the sound carrier and instead deals with the slowly varying complex sound profile only. Our three test cases of Gaussian beams with different waists, strongly interacting with a two-dimensional sound column, show excellent agreement with the analytical treatment and with physical experiments performed in our laboratory.