The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
N. Sven D. Liedberg - One of the best experts on this subject based on the ideXlab platform.
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Load Reduction on a Rigid Pipe: Pilot Study of a Soft Cushion Installation
Transportation Research Record: Journal of the Transportation Research Board, 1997Co-Authors: N. Sven D. LiedbergAbstract:In a project involving the construction of a new link of European Freeway E18, an 800-mm Pipe was to be founded on a cushion of expanded polystyrene under an embankment fill of 9.3 m. In a pilot study measurements were taken of soil-Pipe contact earth pressures around the circumference of the Pipe, vertical earth pressures in the soil above the crown, relative diameter changes of the Pipe in the vertical and the horizontal directions, and Pipe settlements into the cushion. The design of the complete structure was partly done by using the active design program SPIDA (Soil Pipe Interaction Design and Analysis). The results indicate that the safety margin in the design was greater than first expected because the reinforced standard Pipe, designed for only 5 m of fill, was uncracked, even though the height of fill was 9.3 m. The measured deformations of the Pipe were smaller than those expected for the concrete to crack. The earth pressure measurements showed a pronounced soil arching effect in the soil above the Pipe.
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Load Reduction on a Rigid Pipe: Pilot Study of a Soft Cushion Installation
Transportation Research Record, 1997Co-Authors: N. Sven D. LiedbergAbstract:In a project involving the construction of a new link of European Freeway E18, an 800-mm Pipe was to be founded on a cushion of expanded polystyrene under an embankment fill of 9.3 m. In a pilot study measurements were taken of soil-Pipe contact earth pressures around the circumference of the Pipe, vertical earth pressures in the soil above the crown, relative diameter changes of the Pipe in the vertical and the horizontal directions, and Pipe settlements into the cushion. The design of the complete structure was partly done by using the active design program SPIDA (Soil Pipe Interaction Design and Analysis). The results indicate that the safety margin in the design was greater than first expected because the reinforced standard Pipe, designed for only 5 m of fill, was uncracked, even though the height of fill was 9.3 m. The measured deformations of the Pipe were smaller than those expected for the concrete to crack. The earth pressure measurements showed a pronounced soil arching effect in the soil above...
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Load reduction on a Rigid Pipe : Pilot study of a soft cushion installation : Structures
Transportation Research Record, 1997Co-Authors: N. Sven D. LiedbergAbstract:In a project involving the construction of a new link of European Freeway E18, an 800-mm Pipe was to be founded on a cushion of expanded polystyrene under an embankment fill of 9.3 m. In a pilot study measurements were taken of soil-Pipe contact earth pressures around the circumference of the Pipe, vertical earth pressures in the soil above the crown, relative diameter changes of the Pipe in the vertical and the horizontal directions, and Pipe settlements into the cushion. The design of the complete structure was partly done by using the active design program SPIDA (Soil Pipe Interaction Design and Analysis). The results indicate that the safety margin in the design was greater than first expected because the reinforced standard Pipe, designed for only 5 m of fill, was uncracked, even though the height of fill was 9.3 m. The measured deformations of the Pipe were smaller than those expected for the concrete to crack. The earth pressure measurements showed a pronounced soil arching effect in the soil above the Pipe.
Giuseppe Pontrelli - One of the best experts on this subject based on the ideXlab platform.
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BLOOD FLOW THROUGH A CIRCULAR Pipe WITH AN IMPULSIVE PRESSURE GRADIENT
Mathematical Models and Methods in Applied Sciences, 2000Co-Authors: Giuseppe PontrelliAbstract:The unsteady flow of a viscoelastic fluid in a straight, long, Rigid Pipe, driven by a suddenly imposed pressure gradient is studied. The used model is the Oldroyd-B fluid modified with the use of a nonconstant viscosity, which includes the effect of the shear-thinning of many fluids. The main application considered is in blood flow. Two coupled nonlinear equations are solved by a spectral collocation method in space and the implicit trapezoidal finite difference method in time. The presented results show the role of the non-Newtonian terms in unsteady phenomena.
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PULSATILE BLOOD FLOW IN A Pipe
Computers & Fluids, 1998Co-Authors: Giuseppe PontrelliAbstract:Abstract The unsteady flow of blood in a straight, long, Rigid Pipe, driven by an oscillatory pressure gradient is studied. Three different non–newtonian models for blood are considered and compared. One of them turns out to offer the best fit of experimental data, when the rheological parameters are suitably fixed. Numerical results are obtained by a spectral collocation method in space and the implicit trapezoidal finite difference method in time.
Xu Hai-liang - One of the best experts on this subject based on the ideXlab platform.
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Research on the Pump–Vessel Combined Ore Lifting Equipment for Deep-Sea Rigid Pipe Mining System
Journal of Offshore Mechanics and Arctic Engineering, 2008Co-Authors: Xu Hai-liangAbstract:It is known from the principle that the pump-vessel combined ore lifting method has high head, large ores lifting capacity, and long-term working reliability. When applied to the deep-sea Rigid Pipe mining system, the main pump and power equipment installed on the mining ship is more convenient to operate and maintain. According to Bernoulli's equation and two phases of hydrodynamics theory, the ore lifting equipment parameters have been calculated and analyzed. It is known that the pump head H of 1000 m sea mining system is 124-172 m and that of 5000 m sea mining system is 652-760 m. It is known that the pump-vessel combined lifting method is feasible in both theory and practice, therefore it is an ideal ore lifting method for a deep-sea Rigid Pipe mining system.
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Research on the pump-vessel combined ore lifting equipment for deep sea Rigid Pipe mining system
Ocean Engineering, 2007Co-Authors: Xu Hai-liangAbstract:Theoretically speaking,the pump-vessel combined ores lifting method has such advantages as high head,large ores lifting capacity and long-term working reliability.When applied to the deep-sea Rigid Pipe mining system,the main pump and power equipment installed on the mining ship are more convenient to operate and maintain.According to Bernoulli's equation and two phases hydrodynamics theory, the ores lifting equipment parameters have been calculated and analyzed.It is known that the pump-head of 1 000 m sea mining system is 124～172 m and that of 5 000 m sea mining system is 652～760 m,and it is known that the pump-vessel combined lifting method is feasible in both theory and practice.Therefore it is an ideal ores lifting method for the deep sea Rigid Pipe mining system.
Ernest T. Selig - One of the best experts on this subject based on the ideXlab platform.
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Rigid Pipe DISTRESS IN HIGH EMBANKMENTS OVER SOFT SOIL STRATA
Transportation Research Record, 1994Co-Authors: Frank J. Heger, Ernest T. SeligAbstract:Two case histories of severe distress in actual Rigid Pipe installations are presented. They illustrate how soft soils in the region below the outer haunch or adjacent to the Pipe within one diameter beyond the sides of the Pipe resulted in significant increases in the load on the Pipe and the shear and bending stress resultants, producing extensive flexural cracking and failures in diagonal and radial tension. For each installation, the Pipe design and installation designs are presented along with a description of the failure. The results of soil-structure interaction analyses using the computer program SPIDA are presented on the basis of two models, one modeling the soft soils that existed at each side and the other modeling the same installation with the soft soils replaced by compact in situ or placed granular soils. The results show how the presence of soft soils under high fills increases the earth load and structural effects on the Pipe compared with Pipe in conventional installations. The results also show that the Pipes in each of the two installations were not properly designed for the 18- to 20-m (60- to 65-ft) finished heights of fill over the Pipe, even without the presence of the soft soils.
Bang-hua Yang - One of the best experts on this subject based on the ideXlab platform.
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Biomechanical Modeling of the Rectum for the Design of a Novel Artificial Anal Sphincter
Biomedical instrumentation & technology, 2010Co-Authors: Peng Zan, Guozheng Yan, Hua Liu, Bang-hua Yang, Yujuan Zhao, Nianting LuoAbstract:Abstract This paper discusses biomechanical issues that are related to the option of a novel artificial anal sphincter around the human rectum. The prosthesis consists of a compression cuff system inside and a reservoir cuff system outside, which is placed around the debilitated sphincter muscle. The micro-pump shifts fluid between the cuffs and thus takes over the expansion and compression function of the sphincter muscle. However, the human rectum is not a Rigid Pipe, and motion in it is further complicated by the fact that the bowel is susceptible to damage. With the goal of engineering a safe and reliable machine, the biomechanical properties of the in-vivo porcine rectum are studied and the tissue ischemia is analyzed.
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LSMS/ICSEE - Research on the biocompatibility of the human rectum and a novel artificial anal sphincter
Lecture Notes in Computer Science, 2010Co-Authors: Peng Zan, Jinyi Zhang, Yong Shao, Bang-hua YangAbstract:This paper discusses biocompatibility issues that are related to the human rectum and a novel artificial anal sphincter. The artificial anal sphincter system is a novel hydraulic-electric muscle to treat fecal incontinence. A high integration of all functional components and no wire linking to the outer device make the surgical implantation more easy and lower risk. However, the human rectum is not a Rigid Pipe, and motion in it is further complicated by the fact that the bowel is susceptible to damage. With the goal of designing a reliable and safe instrument, the motion model between the artificial anal sphincter and the rectum is developed, the biomechanical material properties of human rectum are analyzed. The results show that the deformation of the artificial anal sphincter can be controlled by the press of reservoir below the upper limit of human tissue ischemia.
