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This paper presents a numerical approach based on the finite element method for the estimation of AC interference on buried metallic pipelines sharing the same right-of-way of power transmission lines in presence of mitigation wires. The proposed approach relies on a hybrid technique in order to reduce the mesh size and, in turn, the computational time. The feasibility of the method is demonstrated with application to a standard interference configuration. Some tests were performed in order to assess how the position and material of the mitigation wires affect the induced current on a buried metallic pipeline.

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In 2016 a new law for public contract was approved in Italy also aimed at improving the national and local sustainable transport planning. The Italian government has also adopted new 'Guidelines for assessment the Investment Projects' derived from the European Commission indications about the external costs of transport estimation in the Cost-Benefit Analysis. Starting from these considerations, the aim of this paper was to propose a new methodology, in compliance with the Italian guidelines, for the estimation of the external costs of transport in a Cost-Benefit Analysis. The application case study was a new tourist railway line in Lazio Region. The external costs estimated were the variations in term of: climate change, air pollution, noises, congestion and road accident. Estimations results allow to conclude that there is a social convenience of this new rail infrastructure because: i) a positive Net Present Value equal to about 27 M€ was estimated; ii) an Internal Rate of Return much greater than the discount rate (9% vs. 3%) was observed; iii) a benefit/cost ratio equal to 2 and a PayBack Period of 15 years was quantified. The overall amount (in monetary value) of external costs saved is about 360 thousand Euros/year (2016 prices) with a cumulative value, for all the life-period considered (30 years), equal to 11 million of Euros.

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The paper presents a method to prevent the water hammer by an adaptive control of the valve closing process. For this purpose, the valve is equipped with a brake system that acts onto the rotation axis of the valve flap. The brake cylinder of the applied hydraulic disk brake is connected to the pipeline just upstream the valve, so that the fluid pressure may activate the brake. By this means the closing is interrupted when the pressure of the fluid increases due to the water hammer. The pressure peak is limited to a maximum pressure given by the user. The described system does not need any external energy source. Furthermore, it adapts to changes of the pipe system parameters, such as varying pipeline length (e.g. liquid supplied from tanks with a different distance from the valve), fluid velocity or physical properties of the fluid. These are major advantages compared to traditional damping systems, which delay valve closing in a fixed manner.

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Crude oil and other liquid materials are transported in large quantities through pipelines. Pipelines are an efficient and safe transport way as compared to both rail and road transportation, both from the economical and environmental points of view. Nevertheless, loss of containment accidents can occur due to external action ea mechanical impact, for examplee or to corrosion, aging, etc. Even though the frequency of such events is certainly very low, the effects and consequences on environment can be very important. The consequences of accidents in pipelines can be efficiently reduced through a suitable design of the whole system. One of the points which must be decided in the design is the installation of blocking valves at appropriate distances, so that emergency shutdowns can interrupt the flow of substance and isolate the section where the loss of containment has taken place. In the case of pipe rupture the amount released is therefore limited to the content between two consecutive valves, usually placed according to heuristic criteria. However, if too many valves are used, the capital cost of equipment increases excessively, and if too few are used, the risk of serious accidents increases. In this paper we consider the possibility of improving the design of such systems by applying riskbased optimization criteria. We propose an optimization methodology to solve this conflict by means of an objective function that analyzes the variations in overall costs, including the cost of the investment (with specific reference to blocking valves) and the cost of accidents. The result is an optimum situation in which costs are kept to a minimum. As an example, we apply the methodology to the transportation of gasoline by pipeline. Peer Reviewed