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Gas Metal Arc Welding (GMAW) are well known due to its cost effective and easy accessibility. The technique is commonly used in shipping maintenance to repair corrosion and erosion affected propeller blades. Recently, studies of the Friction Stir Process (FSP) have shown its capability to generate a very fine microstructure and enhancement of the metal surface properties. This paper proposes an integrated approach for repairing larger sized nickel-aluminum bronze (NAB) components using a single robotic system. The process includes surface cleaning, weld deposition (WD), welding deposition Friction Stir Process (WD-FSP), surface and contour finishing. The mechanical properties, including hardness, cavitation erosion and corrosion performance, are tested on as-cast NAB, WD and WD-FSP surfaces. The weld deposition and WD-FSP surfaces showed an enhancement in hardness compared to as-cast NAB. As for cavitations erosion and corrosion, the weld deposition and WD-FSP sample exhibited an improvement in the cumulative mass loss and shifting of the electrode potential to the more noble section signifying that using the proposed approach is feasible for NAB repair.

Robotic friction stir processing (FSP) has not been widely researched to date. This is perhaps due to the limited force capabilities of industrial robots in comparison with dedicated commercial FSP equipment. When operating a FSP machine, the force used to plunge the tools may range from 5000 to 8000 N which is currently beyond the capability of most robots. However, the capacity of robotic manipulators is increasing, so low force friction stir processing is becoming feasible. The ability of the robot arm to apply a controlled force that is normal to a 3-dimensional surface without the need to reorient the workpiece makes it a very useful tool for FSP of complex components. In this analysis, a robot arm with a capacity of 2500 N is used to improve the surface properties of nickel aluminum bronze (NAB) using low force FSP. Multiple passes were applied to the surface of the test sample for a more consistent spread of the stir zone. The sample was then microhardness tested and demonstrated a 62 pct increase in surface hardness. Cavitation erosion testing of the original and processed surfaces was also performed as per ASTM G-32. The erosion rate of the processed NAB sample was 44 pct of the rate experienced by the original cast NAB sample. Finally, the corrosion potentials of FSP NAB were measured at 45 mV less anodic than the unprocessed material, indicating that the processed material is more noble relative to the cast NAB sample.

Toxic metals like lead, bismuth, mercury and zinc-aranyl have been found to repress the carbonaceous oxygen demand. The biological seed was developed from trade waste of Glaxo Laboratories. Three concentrations: 5, 10 and 15 mg 1 −1 of the metals were used to observe repression of carbonaceous oxygen demand of amino acid, methionine, used as substrate. Rate constants, ratios of ( t / y ) 1.3 and COD: BOD were computed.

Atomic absorption spectrophotometric studies were carried out to detect the presence of Cd and Zn in samples of fifteen commercial fertilisers, fifteen productive soils, eight barren soils, four garden soils and fifteen river water samples. The concentrations of Cd and Zn in fertilisers, productive soils, barren soils, garden soils and river water were recorded as 1·2–7·9 and 17–3070 mg kg −1 , 0·9–5·9 and 55–95 mg kg −1 0·04–0·06 and 7·5–10 mg kg −1 , 0·4–0·75 and 7·8–11 mg kg −1 and 0·5–2·3 and 8·5–18·5 mg litre −1 , respectively. In addition, soil samples were analysed for sand, silt, clay, pH, electrical conductivity, water soluble salts, osmotic pressure, cation exchange capacity, CaCO 3 and organic matter.