The oxidation of organic compounds by Fe(II)/H 2 0 2 (known as Fenton's reagent) has been known for nearly a century. Recently, this reagent has been used in wastewater treatment technology. The scope and the range of applicability of Fenton and Fenton like [Fe(ni)/H 2 0 2 ] reagents in advanced oxidation technology is reviewed and selected examples of their application are presented. The rate of oxidation and the extent of mineralization of organic pollutants with these reagents is improved significantly by irradiation with UV-visible light. The usefulness of UV-visible/ Fe(II)/H 2 0 2 and UV-visible/Fe(III)/H 2 0 2 processes are exemplified through specific applications. Still, much higher improvement in the rate of destruction of organic pollutants is achieved by replacement of Fe(II)/Fe(III) with ferrioxalate.

Methyl tert-butyl ether (MTBE) is a pollutant often found in groundwaters contaminated by gasoline spills or from leaking underground storage tanks. The common techniques often used for the remediation of contaminated water are not very effective for MTBE. This study examines the UV/ H 2 O 2 advanced oxidation technology to determine its effectiveness in the treatment of MTBE. The degradation of MTBE was found to follow pseudo-first-order kinetics, and hence the figure-of-merit electrical energy per order (E EO ) is appropriate for estimating the electrical energy efficiency. The E EO values were found to depend on the concentrations of MTBE, H 2 O 2 , and other components, such as benzene, toluene, and xylenes (BTX). This study shows that MTBE can be treated easily and effectively with the UV/H 2 O 2 process with E EO values between 0.2 and 7.5 kWh/m 3 /order, depending on the initial concentrations of MTBE and H 2 O 2 . The treatment efficiency of 10 mg L -1 MTBE is not adversely affected by the presence of low concentrations of BTX (<2 mg L -1 ). However, the degradation efficiency is significantly decreased at BTX levels greater than 2 mg L -1 . A kinetic model, based on the initial rates of degradation, provides good predictions of the E EO values for a variety of conditions.

Friction stir welding of steel presents an array of advantages across many industrial sectors compared to conventional fusion welding techniques. However, the fundamental knowledge of the friction stir welding process in relation to steel remains relatively limited. A microstructure and property evaluation of friction stir welded low alloy steel grade DH36 plate, commonly used in ship and marine applications has been undertaken. In this comprehensive study, plates of 2000 x 200 x 6 mm were butt welded together at varying rotational and traverse speeds. Samples were examined microscopically and by transverse tensile tests. In addition, the work was complemented by Charpy impact testing and micro-hardness testing in various regions of the weld. The study examined a wide range of process parameters; from this, a preliminary process parameter envelope has been developed and initial process parameter sets established that produce commercially attractive excellent quality welds through a substantial increase in the conventionally recognised weld traverse speed.

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