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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Investigation of the flow in an idealised inlet port/poppet valve assembly

Ahmed, Ashraf Mohamed Yossri January 1986 (has links)
No description available.

An assessment of the performance of high density polyethylene copolymers for natural gas distribution pipes

McNally, Paul F. January 1980 (has links)
The total thermoplastics pipe market in west Europe is estimated at 900,000 metric tonnes for 1977 and is projected to grow to some 1.3 million tonnes of predominantly PVC and polyolefins pipe by 1985. By that time, polyethylene for gas distribution pipe and fittings will represent some 30% of the total polyethylene pipe market. The performance characteristics of a high density polyethylene are significantly influenced by both molecular weight and type of comonomer; the major influences being in the long-term hoop stress resistance and the environmental stress cracking resistance. Minor amounts of hexene-1 are more effective than comonomers lower in the homologous series, although there is some sacrifice of density related properties. A synergistic improvement is obtained by combining molecular weight increase with copolymerisation. The Long-term design strength of polyethylene copolymers can be determined from hoop stress measurement at elevated temperatures and by means of a separation factor of approximate value 22, extrapolation can be made to room temperature performance for a water environment. A polyethylene of black composition has a sufficiently improved performance over yellow pigmented pipe to cast doubts on the validity of internationally specifying yellow coded pipe for gas distribution service. The chemical environment (condensate formation) that can exist in natural gas distribution networks has a deleterious effect on the pipe performance the reduction amounting to at least two decades in log time. Desorption of such condensate is very slow and the influence of the more aggressive aromatic components is to lead to premature stress cracking. For natural gas distribution purposes, the design stress rating should be 39 Kg/cm2 for polyethylenes in the molecular weight range of 150 - 200,000 and 55 Kg/cm2 for higher molecular weight materials.

Rapid crack propagation in polyethylene gas pipes

Yayla, Pasa January 1991 (has links)
No description available.

The mechanical behaviour and fatigue analysis of flexible pipes

Chen, Zhenxin January 1990 (has links)
No description available.

Dynamic crushing of thin-walled tube arrays

Shim, V. P. W. January 1986 (has links)
No description available.

Flow in centrifugal water pump impellers

Rose, Martin George January 1987 (has links)
No description available.

A numerical model for three dimensional viscous flows aimed at centrifugal pump impellers

Silva Lima, Jose Aldo January 1992 (has links)
No description available.

Rotating stall and stability of mismatched compressor stages

Giannissis, G. January 1987 (has links)
No description available.

Fluid/structure interaction in dynamic crack propagation problems

Caldis, E. S. January 1982 (has links)
No description available.

Development of knitted structures for dust filtration

Lawton, Philip John January 1992 (has links)
No description available.

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