Recent experiments at Princeton University have revealed aspects of smooth pipe flow behaviour that suggest a more complex scaling than previously noted. In particular, the pressure gradient results yield a new friction factor relationship for smooth pipes, and the velocity profiles indicate the presence of a power-law region near the wall and, for Reynolds numbers greater than about 400x103 (R...

Pipe inspection is one of the areas that have attracted high research interest for robot applications especially in oil and chemical industry and civil engineering. Robot body rolling while it travels within a pipe has been a problem for accurately collecting inspection data. Under certain circumstances where vision systems have to be employed, robot body rolling may cause vision inspection dat...

Abstract—A large variety of pipe flange is required in marine and construction industry. Pipe flanges are usually welded or screwed to the pipe end and are connected with bolts. This approach is very simple and widely used for a long time; however, it results in high development cost and low productivity, and the productions made by this approach usually have safety problem at the welding area....

Recently several reports of Cryptology ePrint Archive showed the discovering that for a normal iterative hash function the entropy and codomain would reduce greatly,then some conclusions were given: Narrow-pipe hash functions couldn’t resist this reducing (But wide-pipe hash functions could.),and generic collision attacks on narrow-pipe hash functions would be faster than birthday paradox.The d...

The problem of turbulent flow in a rough pipe of arbitrary shape is considered. The classical Izakson-Millikan argument for a logarithmic velocity profile is presented, and matched asymptotic expansions are introduced. Scaled, dimensionless equations are produced and simplified. A simple mixing length turbulence model is presented, which closes the problem. To calibrate the model, the mechanica...

The design of a new laboratory facility for evaluating the structural response of small-diameter buried pipes (e.g., leachate collection pipes in landfills) is presented. The pipe is tested within a 2.0 m wide, 2.0 m long, and 1.6 m high prism of soil, subject to large vertical pressures (1000 kPa), with only minimal roughness and deflection of the lateral boundaries. Results from finite elemen...

Sudden pipe expansions have been known as efficient hydraulic energy dissipaters for a long time. The complex phenomenon of flow separation and velocity discontinuity at the interface of incoming jet and the recirculation flow, results in intensive shear and tensile rupture of the fluid and the associated destructive phenomenon of cavitation. This paper focuses on aeration in sudden pipe expans...

This paper considers the problem of internally inspecting underground pipes, such as sewers, in order to identify and locate major structural defects or damage to the pipes, and to identify potential defects which may lead to failure. It considers three aspects of the pipe inspection task; namely, the extraction of geometric primitives from the pipe image sequences, the tracking of these primit...

[1] Soil pipes were surveyed in 160 British blanket peat catchments using consistent application of ground-penetrating radar. Soil pipes were found in all catchments. The mean frequency of piping was 69 per kilometer of surveyed transect. Land management (moorland gripping) appears to exert the most important control on hillslope pipe frequency in blanket peats. Management practice in peatlands...

This is the ®rst in a series of two papers generated from a study on net-section-collapse (NSC) analysis of circumferentially cracked pipes. In this paper (part I), a generalized NSC method is presented to predict the maximum moment of a circumferentially cracked pipe with a variable-depth internal surface crack subject to combined bending and tension (pressure-induced) loads. Two sets of equat...