Arman Abdullah

Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP), and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR) of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr for Desulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.

Corrosion Study on X70-Carbon Steel Material Influenced by Soil Engineering Properties

Soil as a corrosive medium is probably of greater complexity than other environment. This paper studies the influence of soil engineering properties towards metal loss of buried X70 carbon steel coupons. The study focuses on soil engineering properties which are soil moisture content, clay content and plasticity index. A total of 160 pieces of X70 carbon steel coupon were buried in 5 different locations in Peninsular Malaysia for a period of 12 months to study the effect of the abovementioned parameters towards metal loss caused by soil-corrosion. The samples were retrieved periodically for every 3 months to determine its weight loss and consequently the corrosion rate. It was found that the rapid growth of corrosion is relatively correlated with the high moisture content of soil. Yet, corrosion initiated at a slow pace for high plasticity soil and clayey soil. The highest and the lowest corrosion growth rate were calculated at 0.218mm/year and 0.051mm/year respectively. No strong indication can be found to relate the dominant influence of soil engineering properties towards measured corrosion rate of buried steel coupons.

PreQTender: Web-based prequalification for tender management system in construction projects

Tendering processes need some improvements as they being used widely by government and private sector. The improvements that attempts to apply is to used Web services technology as a medium to process all the tenders that submitted by the interested contractors. This study is to develop an efficient Web application for prequalification tendering processes. Decision Support System (DSS) is used as a tool to help decision making (DMs) for selecting contractors. This work will process tender and it will generate the short listed of the qualified contractors those eligible contractors into the evaluation process.

Qualitative Assessment of Chloride and Sulphate Influence on Soil Corrosivity

External corrosion is a corrosion phenomenon due to the environment or surrounding of the structure. This paper discusses on the influence of chloride and sulphate element on corrosion resistance of steel coupon buried underground. The coupons were placed underground at seven different locations of various soil compositions covering east-coast of Peninsular Malaysia. A total of 132 of steel coupons were installed in a 1.0m-hole and exposed to the subsoil environment for a period of 12-months whereby a periodic retrieval of the coupon were done for every 3-months so that the dynamic growth of metal loss can be measured continuously over time. Soil resistivity test were conducted on the selected sites to determine its corrosiveness level. Parameters such as sulphate and chloride content were measured to correlate with the actual metal loss of buried steel coupons. Site with the highest content of chloride and sulphate yields the most severe loss of metal volume. The findings show that chloride and sulphate contents are highly influential upon corrosion growth rate.