In this paper we study properties of intersection graphs of kbend paths in the rectangular grid. A k-bend path is a path with at most k 90 degree turns. The class of graphs representable by intersections of k-bend paths is denoted by Bk-VPG. We show here that for every fixed k, Bk-VPG ( Bk+1-VPG and that recognition of graphs from Bk-VPG is NP-complete even when the input graph is given by a Bk...

Transmission loss measurements are reported for long steel pipes of circular crosssection, with air inside and out, excited by internal sound. At low frequencies (wavelength greater than the pipe diameter), most of the radiated sound is accounted for by pipe bending waves. In order to approach the much higher transmission loss predicted for pure breathing motion of the pipe, bending waves must ...

Abstract The Downstream Surge Chamber of a pumped storage power station adopts impedance with an upper chamber layout. tailrace tunnel is connected the connecting pipe through right-angle bifurcated and bend. layout type special water flow conditions are complex. To study its hydraulic characteristics, three-dimensional field mathematical model at bottom surge established, variation law charact...

Computational fluid dynamics (CFD) analysis of singlephase and two-phase flow was performed in a 90 degree horizontal to vertical elbow with 12.7 mm inside diameter. Characteristic flow behavior was investigated at six different upstream and downstream locations of the elbow. To evaluate the effects of different phases, three different air velocities and three different water velocities were us...

The purpose of this study was to evaluate the ability of the ulnar nerve motor axons to conduct an evoked action potential at three elbow positions (0 degrees, 90 degrees, and 120 degrees). The latency (from above and below elbow), negative-phase amplitude, and duration of the evoked action potential were used to evaluate the effect of elbow position on 50 normal men. The results indicate that ...

Several rigorous turbulent models have been developed in the past years and it can be seen that more research is needed to reach a better understanding of their generality and precision by verifying their applications for distinct hydraulic phenomena; under certain assumptions. This survey evaluates the performance of Standard k-ε, Realizable k-ε, RNG k-ε, k-ω and RSM models in predicting flow ...