The architect Antonio Gaudi designed complex structures based on catenary systems. His beautiful forms were created by suspending pieces of string from hooks, deforming them with weights and other strings, then inverting the form to create the structural elements. Today’s architects are at a loss to reproduce these types of catenary forms when using even the most advanced design tools on the ma...

Contacts between pantograph and catenary are the most critical parts in the transmission of electrical energy for modern high-speed trains. Contact wire oscillations change combined force between pantograph and catenary, and the contact may even get lost. Therefore special pantographs and catenaries have been developed and further constructive changes are under development. A design criterion i...

Circulating Fluidised Beds (CFBs) are widely applied in the process industry, for mostly gas-solid and gas-catalytic reactions. The riser is the key component of the CFB being the process reactor. The important design parameters are the operating gas velocity (U) and the solids concentration flux (G). The CFB operation starts at moderate to high superficial gas velocities. Its voidage exceeds ~...

Based on results from computational studies and plate casting trials, deficiencies in the steel casting feeding rules as currently published by the Steel Founders’ Society of America (SFSA) were determined. A methodology for the development of improved steel casting feeding rules was established based on the Niyama criterion determined from simulation. Newly developed feeding rules using this m...

Long flexible cylinders (e.g. risers, tendons, mooring lines) exposed to the marine environment encounter ocean currents leading to vortex-induced vibration (VIV). These oscillations, often driven at high frequencies over extended periods of time may result in structural failure of the member due to fatigue damage accumulation. Recent developments in instrumentation and installation of data acq...

The use of composite materials in offshore engineering for deep sea oil production riser systems has drawn considerable interest due to the potential weight savings and improvement in durability. The design of composite risers consists of two stages: (1) local design based on critical local load cases, and (2) global analysis of the full length composite riser under global loads and assessment ...

Previous theoretical investigations of translating cables have been focused on the sagged cable equilibrium referred to here as the minimum cutenary. The minimum catenary is stable for finite translation speeds [ 1,2] and asymptotically approaches a buckling instability as the translation speed tends to infinity [2]. Experimental evidence presented in this paper validates this conclusion and th...

Risers are considered vital parts on fluidized catalytic cracking (FCC) conversion units. It is inside the riser that the heavy hydrocarbon molecules are cracked into petroleum fractions such as gasoline and liquefied petroleum gas (LPG). A simplified kinetic flow model in combination with the Tank-In-Series model was used to predict the conversion response of an FCC riser to changes in feed te...

Human embryos aged six and one-half through 12 weeks were studied to determine the morphological changes in shape of the maxillary dental arch during this early developmental period. Age was determined by crown-rump lengths using the table of Patten ('53). When compared to a reference catenary curve, the embryonic dental arch exhibited several time-linked and directional changes in shape. First...