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...

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...

The pressure drop for air-water two-phase flow in pipeline systems with S-shaped and vertical risers at various inclinations (−1°, −2°, −4°, −5° −7° from horizontal) was predicted using an artificial neural network (ANN). In the designing of ANN model, superficial velocity gas liquid as well inclination downcomer were used input variables, while values flows determined output. An a hidden layer...

This paper described the discovering process of some shortcomings of the conventional fluid catalytic cracking (FCC) process and the proposed two-stage riser (TSR) FCC process for decreasing dry gas and coke yields and increasing light oil yield, which has been successfully applied in 12 industrial units. Furthermore, the multifunctional two-stage riser (MFT) FCC process proposed on the basis o...

Optimum casting designs are unreliable without consideration of the statistical and physical uncertainties in the casting process. In the present research, casting simulation is integrated with a general purpose reliability-based design optimization (RBDO) software tool previously developed at the University of Iowa. The RBDO methodology considers uncertainties in both the input variables as we...

To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the "HYSY-981" ocean oil drilling platform. No welding and pasting were used when the sensor was insta...

Now a days, significant amount of aluminium alloy are being used to fabricate components such as engine blocks, cylinder heads, suspension control arms, wheels and pistons. In response to consumer demands for the increase in performance, the use of aluminium has grown dramatically in the recent years. So in order to produce a sound LM6 (Al-12%Si) Aluminium alloy casting, a new approach is made ...

This study presents an alternative methodological approach for thermal rating of power cables installed in vertical risers covered by unvented circular protective guards. An analogue thermal-electrical circuit is proposed for the thermal analysis of cables inside vertical risers. The proposed equivalent analogue model is verified by means of indoor experiments and finite-element simulations wit...