Nordin Yahaya - Academia.edu (original) (raw)

Papers by Nordin Yahaya

Polymeric composites are being increasingly used as repair material for repairing critical infras... more Polymeric composites are being increasingly used as repair material for repairing critical infrastructures such as building, bridge, pressure vessel, piping and pipeline. Technique in repairing damaged pipes is one of the major concerns of pipeline owners. Considerable researches have been carried out on the repair of corroded pipes using composite materials. This article attempts a short review of the subject matter to provide insight into various techniques used in repairing corroded pipes, focusing on a wide range of composite repair systems. These systems including pre-cured layered, flexible wet lay-up, pre-impregnated, split composite sleeve and flexible tape systems. Both advantages and limitations of these repair systems were highlighted. Critical technical aspects have been discussed through the current standards and practices. Research gaps and future study scopes in achieving more effective design philosophy are also presented.

The paper presents a probabilistic-based methodology for the assessment of a pipeline containing ... more The paper presents a probabilistic-based methodology for the assessment of a pipeline containing internal corrosion defects. Two different models have been used to predict the future CO2 corrosion rates namely a linear growth and the deWaard-Milliams models. A probabilistic approach is used to analyse the behaviour of corrosion data obtained from in-line intelligent (ILI) pigging inspections. The outcomes are parameters represented by their corresponding statistical distribution. Due to the availability of these statistical parameters, a Monte Carlo simulation is used to calculate the probability of failure of the pipeline due to bursting failure. The existence of corrosion may reduce the maximum capacity of the pipe, as such causing leakage and bursting when the operational pressure supersedes its threshold. From the analysis of the result, failure probability based on theoretical linear growth model exhibit slightly longer lifetime of the pipeline with three years interval compare...

Inspection data obtained from in-line inspection can be used to assess present integrity as well ... more Inspection data obtained from in-line inspection can be used to assess present integrity as well as to predict future integrity of corroding pipeline by using a combination of probabilistic analyses and simulation process. However, numerical errors arise when all the inspection data including non-extreme and extreme measured defects were used. In this study, a combination of an extreme value distribution and peaks-over-threshold method was adopted to analyse the effect of extreme data upon pipeline reliability. The paper focuses on the elimination of the "low-risk" data in the analysis in order for extreme values to be significantly emphasized. The study found that the high threshold value would lead to the high failure probability. The optimum threshold value is constrained by the number of remaining data. The selection of threshold and extreme distribution value must be cautiously carried out to minimise the possibilities of over predict the pipeline's time to failure.

A semi-probabilistic methodology for predicting the remaining strength of submarine pipelines sub... more A semi-probabilistic methodology for predicting the remaining strength of submarine pipelines subjected to internal corrosion based on Recommended Practice RP-F101 by Det Norske Veritas (DNV) is described in this paper. It is used to estimate the maximum allowable operating pressure of the corroding pipelines based on series of pigging data, which represents the corrosion pit location and dimension. The introduction of partial safety factors in the DNV code to minimise the effect of uncertainties due to the defect sizing has improved the reliability of pipeline assessment methodology. Nevertheless, the code is still regarded as a fully deterministic approach due to its incapability of predicting the remaining life of corroded pipeline. Thus, we have added prediction capabilities to the capacity equation by introducing a standard deviation model of future defect depth. By doing so, the variation of safety factors of the capacity equation can be fully manipulated where prediction of f...

Soil corrosion is a serious threat to the integrity of buried structures such as underground stor... more Soil corrosion is a serious threat to the integrity of buried structures such as underground storage tanks, oil and gas transmission pipelines, and many other structures. This paper investigates the effects of soil engineering properties towards metal loss of buried X70 carbon steel coupons. The study focuses on soil engineering properties which are soil clay and moisture content. A number of 160 pieces of X70 carbon steel coupon were installed underground in five different locations in Peninsular Malaysia for 12 months period to study the influence of the above mentioned parameters towards metal loss caused by soil-corrosion. The samples were retrieved every 3 months to determine its weight loss and corrosion growth rate over time. The result shows that the rapid growth of corrosion is relatively correlated with the high moisture content of soil. Yet, corrosion initiated at a slow rate for clayey soil. Soil moisture content was found more influential towards corrosion dynamic as co...

journal of engineering science and technology, 2016

Microbiologically influenced corrosion (MIC) is significant to the presence of microorganisms suc... more Microbiologically influenced corrosion (MIC) is significant to the presence of microorganisms such as sulfate reducing bacteria (SRB) in the deterioration of metallic and non-metallic materials. Bacterial chemical biocides are commonly used to disinfect microorganism effectively. Yet, the practice has some negative impact on the environment since the chemical content may cause pollution. A laboratory experimental investigation was conducted to explore the performance of Ultraviolet (UV) radiation in exterminating SRB as an option to replace biocides usage. The morphologies of the isolated Sg. Ular SRB used in this study were related to Desulfovibrio species. An experimental work was conducted in determining the optimum pH and temperature for the SRB to grow before disinfection purposes. The experimental result showed optimum growth for respective SRB were at pH of 8.5 with temperature recorded at 37°C. UV radiation with wavelength of 254 nm was utilised to disinfect the microorganis...

ARPN journal of engineering and applied sciences, 2016

Carbon steels are commonly used as structural materials of piping systems in oil and gas industry... more Carbon steels are commonly used as structural materials of piping systems in oil and gas industry because of their lower cost and wider availability despite their relatively lower corrosion resistance. This work investigates the preferable growth media for Sulfate Reducing Bacteria to proliferate rapidly and the effect of Microbiologically Influenced Corrosion activity towards carbon steel API 5L X-70 line pipe. Present research work highlighted that the preferred growth medium for ATCC 7757 and BARAM is Modified Baar's and Postgate C for Sg. Ular types of SRB. In addition, the corrosion rate was calculated using data based on metal weight loss experiment. The result confirmed that the corrosion rate in biotic (presence of Sulfate Reducing Bacteria) environment is much higher compared to abiotic environment (absence of Sulfate Reducing Bacteria). The pitting morphology that developed with time due to SRB activity was characterized with Field Emission Scanning Electron Microscopy...

International Journal of Strategic Property Management, 2019

In a situation of growing water demand, inadequate public funding, poor asset condition and lack ... more In a situation of growing water demand, inadequate public funding, poor asset condition and lack of maintenance in developing countries, public-private partnerships (PPPs) play an important role in the development of infrastructure, such as water supply and sewerage services. The purpose of this study is to develop a quantitative approach to appropriate risk allocation, with attention directed to the impact of positive and negative factors in water and sewerage projects. The paper presents a hybrid SWARA-COPRAS approach to examine risk allocation, particularly for PPP water supply and sewerage projects in the context of Malaysia. In addition to PPP infrastructure projects, the approach has the potential to be adapted to other applications. The proposed method enables decision makers to utilise qualitative linguistic terms in the allocation of risk between the public and private sector, and to select the best strategy for risk allocation in a contract. Finally, 24 significant risks w...

Journal of Pressure Vessel Technology, 2017

A statistical predictive model to estimate the time dependence of metal loss (ML) for buried pipe... more A statistical predictive model to estimate the time dependence of metal loss (ML) for buried pipelines has been developed considering the physical and chemical properties of soil. The parameters for this model include pH, chloride content, caliphate content (SO), sulfide content, organic content (ORG), resistivity (RE), moisture content (WC), clay content (CC), plasticity index (PI), and particle size distribution. The power law-based time dependence of the ML was modeled as P = ktv, where t is the time exposure, k is the metal loss coefficient, and v is the corrosion growth pattern. The results were analyzed using statistical methods such as exploratory data analysis (EDA), single linear regression (SLR), principal component analysis (PCA), and multiple linear regression (MLR). The model revealed that chloride (CL), resistivity (RE), organic content (ORG), moisture content (WC), and pH were the most influential variables on k, while caliphate content (SO), plasticity index (PI), an...

Research Journal of Applied Sciences, Engineering and Technology, 2015

Underground steel pipelines are the most efficient ways to transport oil and gas over a long dist... more Underground steel pipelines are the most efficient ways to transport oil and gas over a long distance. Steel pipes are considerably susceptible to deteriorate due to corrosion that can lead to serious pipeline failure. The application of fibre-reinforced composite overwrapped with epoxy grout on a damaged circular or rectangular structure is often practiced by the industry. The mechanical properties of the epoxy grouts are critical to their potential application as infill materials in pipeline repair. In this study, the mechanical behaviour of two epoxy based grouts was investigated. The mechanical tests were carried out accordance to the ASTM D695 for the compressive test, the ASTM D790 for the flexural test and the ASTM D638 for the tensile test. From the tests results, the compressive strength and stiffness of the grouts are found to be 60-88 MPa and 2.8-4.9 GPa, respectively. The flexural and tensile strengths of the grouts are found to be within the ranges of 35-43 MPa and 19-33 MPa, respectively. The flexural modulus was recorded at 3.91-11.87 GPa while tensile modulus range is within 2.07-4.65 GPa. From this study, it is concluded that the mechanical properties of the both grouts have the potential to be used in structural rehabilitation as suggested properties in previous research. In addition, for compressive strength, flexural strength and tensile strength less than 90, 45 and 35 MPa, both grouts can be considered as capable to serve its repair purpose in repair and rehabilitation.

Asian Journal of Scientific Research, 2015

The impact of onshore oil and gas pipeline accident i.e., explosion varies depending on the pipel... more The impact of onshore oil and gas pipeline accident i.e., explosion varies depending on the pipeline location, transported product, proximity of residential areas and etc. Pipeline owner's reputation is threatened once an accident takes place, which influences stakeholders' perceptions consequently. This study focuses on prioritizing the importance of the reputation loss factors according to the experts' judgments. Twenty two reputation loss factors were identified from 10 major pipeline explosion post-accident case studies. Nine experts were interviewed to rate importance level of the reputation loss factors using 10-point Likert scale rating method. The significance difference was obtained by the implementation of statistical analysis. Relative Importance Index (RII) was used to identify the importance level of the factor and Analytical Hierarchy Process (AHP) method for prioritization process with the aid of Super Decisions software. Results show that all reputation loss factors are categorized within index number 4-10. The first factor with the highest importance value and priority vector corresponds to each stakeholder for both RII and AHP methods are similar, i.e., A2 "Services or sales progress disturbed", B1"Loss of customer confidence", D3 "Severity of accident" and C4 "CEO refuses to take responsibility". "Job application for positions reduced" is the least priority. Thus, understanding the importance of the reputation loss factors and identifying the priority of which factor to be taken care of are suggested to the pipeline operators in the post-accident responses. Hence, the reputation loss impact can be reduced and annual profit margin is secured.

Jurnal Teknologi, 2015

Pipelines play an extremely important role in the transportation of gases and liquids over long d... more Pipelines play an extremely important role in the transportation of gases and liquids over long distance throughout the world. Internal corrosion due to microbiologically influenced corrosion (MIC) is one of the major integrity problems in oil and gas industry and is responsible for most of the internal corrosion in transportation pipelines. The presence of microorganisms such as sulfate reducing bacteria (SRB) in pipeline system has raised deep concern within the oil and gas industry. Biocide treatment and cathodic protection are commonly used to control MIC. However, the solution is too expensive and may create environmental problems by being too corrosive. Recently, Ultraviolet (UV) as one of the benign techniques to enhance mitigation of MIC risk in pipeline system has gained interest among researchers. An amount of 100 ml of modified Baar’s medium and 5 ml of Desulfovibrio vulgaris (strain 7577) seeds was grown in 125 ml anaerobic vials with carbon steel grade API 5L-X70 coupon...

International Journal of Biological Chemistry, 2015

In oil and gas industry, corrosion due to activity of microorganism is one of the main factors, w... more In oil and gas industry, corrosion due to activity of microorganism is one of the main factors, which contribute to catastrophic structural failure. Previous study always linked Sulfate-Reducing Bacteria (SRB) upon the mechanism of Microbiologically Influenced Corrosion (MIC), as the major contributors. In this study, mechanisms of SRB genus D. vulgaris in terms of bacterial growth under influence of environmental factors were investigated. The growth of pure strain ATCC 7757 and SRB isolated from the soil in suspected areas in Peninsular Malaysia were investigated by using turbidity measurement. Results from the study were analyzed statistically to show the significant influence due to various environmental factors. The results agreed that variation of each environmental parameter tested gives strong influence upon bacterial growth for SRB strain individually.

Journal of Civil Engineering and Management, 2015

Risk assessment is one of the most important factors in achieving success in public-private partn... more Risk assessment is one of the most important factors in achieving success in public-private partnership (PPP) projects. Some relationships between risks in freeway projects have been established. The occurrence of each risk can worsen the effects of others such as a negative impact of financial risks on construction risks. This paper is aimed at prioritizing significant risks in freeway PPP projects applying a fuzzy analytic network process (FANP) method for overcoming the problems of interdependencies and feedback among different risk-ranking alternatives. Data on the study have been collected through a literature review, an interview and a questionnaire survey distributed to experts in the field of freeway PPP projects. The obtained results have shown that financial, legal and political risks are the most significant groups, although improper design, changes in the value of granted lands and the termination of concession are the most important risks. The findings help with strengt...

Applied Mechanics and Materials, 2015

Consequence assessment is an integral part of risk assessment process. There are many types of co... more Consequence assessment is an integral part of risk assessment process. There are many types of consequences loss due to pipeline failure such as assets loss, environmental loss, production loss and human health and safety (HSE) loss. Yet, some of these factors are often neglected in environmental loss assessment such as agricultural, demographic, industrial and local factors. In real life problem solving, the factors of environmental consequence are not assessed precisely due to unquantifiable, deficient and lack of knowledge on the real on-site parameters. These limitations lead to the use of fuzzy-based approaches in environmental consequence assessment using on-site parameters as the main focused on this paper. Even though the basic model can be comparable to other established model, a lot of customization needs to be carried out network-wise, based on the carried products by the pipeline, locally applicable regulations and geographical surroundings. Knowledge of local conditions...

Pipelines those have been buried under seabed sediment are at risk of corrosion due to the corros... more Pipelines those have been buried under seabed sediment are at risk of corrosion due to the corrosiveness of this particular environment. Hereby, corrosion experimental study has been conducted to highlight the importance of near shore sediment as an aggressive environment towards steel structures. Coupons made from API X70 steel of actual pipe have been considered to calculate the corrosion rate by means of weight lost determination at both near shore and offshore areas. The results show that the corrosion rates of coupons buried at near shore area were higher than corrosion rates at offshore. Convincingly, near shore environment has shown a significant influence on corrosion rates of steel pipelines.

Soil resistivity influences the corrosion of metals installed underground and can serve as an ind... more Soil resistivity influences the corrosion of metals installed underground and can serve as an indicator of soil corrosiveness. From corrosion engineering perspective, the lower the resistivity, the higher the corrosivity and vice versa. Soil resistivity is most often measured using Wenner four-electrode method and resistance meter. The aim of this paper is to evaluate the influence of soil resistivity upon metal loss as experienced by corroding steel coupon. The steel coupons were installed underground for duration of 12-months at five different sites in Peninsular Malaysia. Results show that a negative correlation represents the relationship between soil resistivity and corrosion rate. Negative logarithmic model gives the best correlation among corrosion rate and soil resistivity. It also reveals that the relationship is time dependent whereby the longer the steel coupon being exposed to underground environment, the better the correlation. The outcome indicates that the measurement of soil resistivity can act as an early indicator of the potential of corrosion growth rate.

This paper investigated the performance of low frequency ultrasound radiation in mitigating the m... more This paper investigated the performance of low frequency ultrasound radiation in mitigating the microbiologically influenced corrosion (MIC) by mechanically inhibiting the planktonic sulfate-reducing bacteria (SRB) growth in modified ATCC broth number 1249 medium. Several samples contained a laboratory SRB strain of Desulfovibrio vulgaris ATCC 7757 were

Journal of Chemistry, 2014

Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the... more 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 ...

Journal of Environmental Science and Technology, 2014