In airlift reactors transport phenomena are achieved by pneumatic agitation and circulation occurs in a defined cyclic pattern through a loop. In the present work, the effect of geometrical relations on gas holdup and liquid velocity, and consequently on the gas-liquid mass transfer coefficient, was studied in a 6liter airlift bioreactor with AD/AR = 0.63; AD, downcomer cross-sectional area, an...

Flexible riser is a class of flexible pipes which is used to connect subsea pipelines to floating offshore installations, such as FPSOs (floating production/storage/off-loading unit) and SS (semisubmersible) platforms, in oil and gas production. Flexible risers are multilayered pipes typically comprising an inner flexible metal carcass surrounded by polymer layers and spiral wound steel ligamen...

In order to predict the performance of a riser sleeve using simulation software, the thermophysical properties of that sleeve must be known. Current literature gives little to no information about these properties. Some manufacturers have given these properties as an optional module for simulation software without revealing their actual values. The accuracy of these “black box” properties is un...

many procedures suggest for reduction of responses of riser to vortex induced vibrations (viv). natural frequencies of marine risers is an important parameter that can affect the responses of riser to viv. change of riser properties such as top tension and bending stiffness can alter natural frequencies. in this study effects of riser specifications on the responses and fatigue damage of marine...

As oil and natural gas production continue to go deeper into the ocean, flexible riser, as a connection surface of marine channel, will confront greater problems in its practical application. Composite materials are being considered replace steel unbonded pipe order successfully meet lightweight high-strength criteria ultra-deep-water production. The carbon-fiber-reinforced material substitutes...

Changes in shape of the mandibular dental arch were demonstrated in a developmentally representative sample of human embryos. Each reconstructed arch was described in terms of a conformance to a reference geometric curve; ie, catenary. Cross-sectional sample trends showed that the initial dental lamina is anteroposteriorly flattened during the sixth week and begins a progressive elongation and ...

CFBs are widely used in the chemical, mineral, environmental and energy process industries. Several authors stressed the need for a clear identification of the different operation regimes in the riser of a CFB, to ensure a better comprehension of the hydrodynamic context, and thus better define the operation and design parameters.. First approaches to develop a "work map" of the riser operation...

Statoil has designed and tested dual diameter pipeline pigs to perform various tasks during operations, precommissioning and commissioning of the 710km 42"x28" Åsgard pipeline. The concepts developed have been put through a major design and testing program to demonstrate that the various functional requirements have been met. The paper describes the development process as well as field experien...