When a natural gas pipeline ruptures, the adjacent automatic line control valves (ALCVs) should close quickly to prevent leakage or explosion. The differential pressure set point (DPS) at each valve location is the main criteria for value setting in ALCV action. If the DPS is not properly adjusted, the ALCV may mistakenly close or it may not take any action at proper time. This study focused on...

This paper reports the outcome of applying two di erent low-Reynolds-number eddy-viscosity models to resolve the complex three-dimensional motion that arises in turbulent ows in ducts with 90◦ bends. For the modelling of turbulence, the Launder and Sharma low-Re k– model and a recently produced variant of the cubic non-linear low-Re k– model have been employed. In this paper, developing turbule...

A computational and experimental study is reported of turbulent flow around a square-sectioned U-bend with a mean bend radius equal to 3.375 times the hydraulic diameter (DH): the duct Reynolds number is 58,000. The bend geometry is the same as that for which Chang et al. (1983) have reported extensive LDA data except that in the latter experiment the bend was preceded by some thirty hydraulic ...

The Flp site-specific recombinase from Saccharomyces cerevisiae induces DNA bending upon interaction with the Flp recognition target (FRT) site. The minimal FRT site is comprised of two inverted binding elements which flank a central core region. Binding of a single monomer of Flp to DNA induces a DNA bend of 60 degrees. The position of this bend differed depending on whether the substrate cont...

Bull sperm extracted with 0.1% Triton X-100 can be reactivated to full motility with 0.33 mM Mg-ATP (sperm models). When motile sperm models are treated with 0.66 mM NiSO4, spontaneous motility is lost. During the transition to motility arrest, the beat becomes progressively more asymmetric, finally arresting at one extreme of the beat cycle. After spontaneous motility has been lost, the flagel...

in this research an algorithm based on monte carlo simulation is introduced to assess the risk of fire following earthquake in residential, industrial, educational, and governmental land-uses in district no. 20 of tehran. the proposed algorithm consist of different modules including hazard analysis, vulnerability assessment, leak and break analysis of damaged pipeline, ignition probability anal...