Abstract: A method to assess external corrosion in buried pipelines includes analysis of moisture content of soil along the length of the pipe to choose the most appropriate indirect inspection methods. External corrosion is assessed based on the unification of probability techniques using clustered inspection data and deterministic formulation for soil conditions. A deterministic model pinpoints the location of the most likely areas for corrosion due to the electrochemical cell formation produced by the presence of water and the properties of the soil, such as ion concentrations, pH, soil resistivity, redox potential, corrosion potential and soil type. The filtering of the data by clustering provides reliable results to locate the most corrosive locations. The failure probability is calculated based on in-line inspection data, where different indications could appear and different dimensions are used to link the corrosivity with the failure for choosing repairing methods and taking actions against corrosion.

Abstract: A method to assess external corrosion in buried pipelines includes analysis of moisture content of soil along the length of the pipe to choose the most appropriate indirect inspection methods. External corrosion is assessed based on the unification of probability techniques using clustered inspection data and deterministic formulation for soil conditions. A deterministic model pinpoints the location of the most likely areas for corrosion due to the electrochemical cell formation produced by the presence of water and the properties of the soil, such as ion concentrations, pH, soil resistivity, redox potential, corrosion potential and soil type. The filtering of the data by clustering provides reliable results to locate the most corrosive locations. The failure probability is calculated based on in-line inspection data, where different indications could appear and different dimensions are used to link the corrosivity with the failure for choosing repairing methods and taking actions against corrosion.

Abstract: A semiconductor device is manufactured by forming a mask having a first opening and a second opening wider than the first opening on a principal surface of a first conductivity type semiconductor substrate, etching semiconductor portions of the first conductivity type semiconductor substrate exposed in the first and second openings to thereby form a first trench in the first opening and form a second trench deeper than the first trench in the second opening, and filling the first and second trenches with a second conductivity type semiconductor to concurrently form an alignment marker for device production and a junction structure of alternate arrangement of the first conductivity type semiconductor and the second conductivity type semiconductor. In this manner, it is possible to provide a semiconductor device in which a parallel pn structure and an alignment marker can be formed concurrently to improve the efficiency of a manufacturing process.

Abstract: A semiconductor device is manufactured by forming a mask having a first opening and a second opening wider than the first opening on a principal surface of a first conductivity type semiconductor substrate, etching semiconductor portions of the first conductivity type semiconductor substrate exposed in the first and second openings to thereby form a first trench in the first opening and form a second trench deeper than the first trench in the second opening, and filling the first and second trenches with a second conductivity type semiconductor to concurrently form an alignment marker for device production and a junction structure of alternate arrangement of the first conductivity type semiconductor and the second conductivity type semiconductor. In this manner, it is possible to provide a semiconductor device in which a parallel pn structure and an alignment marker can be formed concurrently to improve the efficiency of a manufacturing process.