Perforation in internal upset transition zone is one of the main failure styles for drill pipes. Due to the flow channel specificity of upset transition zone, in this paper, drill pipe failure analysis from the point of flow erosion was put forward. Flow field of drilling fluid in the internal upset transition zone of U127 mm API IEU S135 drill pipe under various conditions were obtained using ...

Given the rapid progress in the electronics industry, the thermal management of electronics components becomes an important and serious issue. Natural and forced cooling are often deficient. One possibility for heat dissipation for high heat flux is using loop heat pipe. A loop heat pipe (LHP) is a two-phase device with extremely high effective thermal conductivity that utilizes pressure differ...

The spring-driven ball-type check valve is one of the most important components of hydraulic systems: it controls the position of the ball and prevents backward flow. To simplify the structure, the spring must be eliminated, and to accomplish this, the flow pattern and the behavior of the check ball in L-shaped pipe must be determined. In this paper, we present a full-scale model of a check bal...

Visual inspection by a human operator has been mostly used up till now to detect cracks in sewer pipes. In this paper, we address the problem of automated detection of such cracks. We propose a model which detects crack fractures that may occur in weak areas of a network of pipes. The model also predicts the level of dangerousness of the detected cracks among five crack levels. We evaluate our ...

Evolution Programs (EPs), including Genetic Algorithms and Evolution Strategies, are well-suited for pipe network optimization problems due to the large number of candidate solutions to be examined, non-linearity of the problem and discrete decision space. However, pipe network problems are highly constrained and random initialization and standard genetic operators often cause infeasibility of ...

Acoustical data transmission through the wall of drill pipes is considered. Drill pipes are known to behave like bandpass filters; the position of the pass bands can be determined analytically. This work extends the frequency domain drill pipe models presented by Barnes and Kirkwood J. Acoust. Soc. Am. 51, 1606–1608 1972 , and more recently by Drumheller J. Acoust. Soc. Am. 85, 1048–1064 1989 ....

This paper describes a vision processing architecture which together with a robotic camera platform and control subsystem comprise a multi-processor real-time system for research into active vision. Experimentation in time-critical aspects of the active vision paradigm over several years has demonstrated the flexibility of “pipe-groups” used as the building block in the system. The design of th...

Spatially regulated transcription of the pipe gene in ventral cells of the Drosophila ovary follicle cell epithelium is a key event that specifies progeny embryo dorsal-ventral (DV) polarity. pipe encodes ten putative protein isoforms, all of which exhibit similarity to vertebrate glycosaminoglycan-modifying enzymes. Expression of one of the isoforms, Pipe-ST2, in follicle cells has previously ...

Downward turbulent bubbly flows in pipes were modeled using computational fluid dynamics tools. The Hydrodynamics, phase distribution and turbulent structure of twophase air-water flow in a 57.15 mm diameter and 3.06 m length vertical pipe was modeled by using the 3-D Eulerian-Eulerian multiphase flow approach. Void fraction, liquid velocity and turbulent fluctuations profiles were calculated a...

This paper gives an example of how predictive models of the deterioration of reinforced concrete pipes and the consequences of failure can be used to develop risk-based replacement strategies for redundant reinforced concrete pipe networks. It also shows how an accurate deterioration prediction can lead to a reduction of agency costs, and illustrates the limitation of the incremental interventi...