Abstract In fluid mechanics, the large pressure fluctuation caused by rapid change of flow in a closed pipeline is called water hammer. It has huge destructive power for pressurized pipelines, which often lead to leakage or even burst. this paper, through analysis dynamic characteristics gas pipeline, necessity setting air valve drawn. Then based on Bentley HAMMER model, combined with example r...

When I was asked to contribute to a volume dedicated to Thomas Ottmann’s sixtieth birthday, I immediately agreed. I have known Thomas for more than 25 years, I like him, and I admire his work and his abilities as a cyclist. Of course, when it came to start writing, I started to have second thoughts. What should I write about? I could have taken one of my recent papers. But that seemed inappropr...

We report on an adapted version of the Bentley-Ottmann algorithm for computing all the intersection points among the edges of the projection of a three-dimensional graph. This graph is given as a set of vertices together with their space Euclidean coordinates, and a set of edges connecting them. More precisely, the three-dimensional graph represents the approximation of a closed and smooth impl...