Hexametaphosphate tends to increase release of both particulate and soluble lead to drinking water. For every mg/L of residual hexametaphosphate, soluble lead increased by 1.6 – 2.5 mg/L after 72 hour stagnation in pure lead pipes compared to the same condition dosed with orthophosphate. Utilities should consider these adverse effects whenever polyphosphate is used to prevent scaling or iron pr...

Pipelines are extensively used engineering structures which convey fluid from one place to another. Most of the time, pipelines are placed underground and are encumbered by soil weight and traffic loads. Corrosion of pipe material is the most common form of pipeline deterioration and should be considered in both the strength and serviceability analysis of pipes. The study in this research focus...

This paper presents a computational framework for implementing an advanced Monte Carlo simulation method, called Subset Simulation (SS) for time-dependent reliability prediction of underground flexible pipelines. The SS can provide better resolution for low failure probability level of rare failure events which are commonly encountered in pipeline engineering applications. Random samples of sta...

The ultrasonic inspection technique can be very useful to determine the state of non reachable structure. In this paper a method based on the neural network classification to evaluate the corrosion level of non accessible pipes is shown. A set of optimal features constitutes the database and feeds the neural network. These features are chosen by time and frequency features extracted from simula...

Internal pipeline corrosion in oil production and transportation is always associated with the presence of water, and the likelihood of corrosion generally increases with the volume fraction of water. When the walls of the pipeline are wetted with oil no corrosion is possible. Highly turbulent flow was associated with negligible corrosion due to water entrainment by the flowing oil, whereas low...

Basically robots are designed in such way that they remove human intervention from labour intensive and hazardous work environment; sometimes they are also used to explore inaccessible work places which are generally impossible to access by humans. The inspection of pipe comes in same category because they carry toxic chemicals, fluids and most of the time has small internal diameter or bends w...

Extreme Value Analysis can be used to extrapolate sample inspection data into uninspected regions of a component. These methods can be used in conjunction with structural reliability software to predict the probability of future failure of the component. This information can help both operators and regulators make risk-based decisions on the future operation of the plant. This paper illustrates...

The Canadian Journal of Chemical Engineering, Volume 81, February 2003 Complex flows with boundary layer separation and reattachment commonly occur in situations of practical interest. In such flows, any accompanying heat or mass transfer is strongly influenced by the fluid dynamics. For example, rates of heat or mass transfer to the wall can have large variations in the reattachment region. In...

The exhaust system has a number of requirements to fulfil. The major ones are to reduce the noise level created by the engine, to channel the waste gases out the rear of the automobile, to minimize the reduction in engine performance, and to have an acceptable service life and cost1. The exhaust system is divided into two main parts, the hot end and the cold end. The components comprising the h...

Failures in cast iron water mains are more complex and diverse than is widely understood in the industry. This paper discusses the modes and causes of pipe failures that have been encountered during a three year investigation by the National Research Council Canada. In addition to corrosion, manufacturing defects, human error and unexpected levels of pipe loading all play a role in the large nu...