The main theorem says that any module-finite (but not necessarily commutative) algebra Λ over a commutative Noetherian universally catenary ring R is catenary. Hence the ring Λ is catenary if R is Cohen-Macaulay. When R is local and Λ is a Cohen-Macaulay R-module, we have that Λ is a catenary ring, dim Λ = dimΛ/Q + htΛQ for any Q ∈ Spec Λ, and the equality n = htΛQ− htΛP holds true for any pair...

Abstract The mooring and riser system is the most critical part of an offshore oil terminal. Traditionally, these two parts are designed separately without considering nonlinear interaction between them. Thus, present paper aims to develop integrated design process for systems with a lazy-S configuration in catenary anchor leg (CALM) One important criteria considered this offset diagram safe op...

Pantograph current collectors, especially for high-speed trains, need to ensure safe contact with the catenary under stringent requirements on the dynamic contact force. A novel, high-dynamic pantograph test rig with accurate virtual catenary emulation is presented that allows for efficient, realistic, and reproducible testing. The complex dynamics of the pantograph/catenary interaction is mode...

Abstract Free-standing hybrid risers are vertical slender steel pipes that commonly used in the oil and gas industry. These structures subjected to complex hydrodynamic loads results fatigue damage. The tidal forces develop on Freestanding Risers (FSR) with buoyancy cans ( BC ) because of varying outer pipe dimensions investigated this work. study considered riser diameters 0.2, 0.3, 0.5 0.6 me...

We call a module M , quasi-catenary if for each pair of quasi-prime submodules K and L of M with K L all saturated chains of quasi-prime submodules of M from K to L have a common finite length. We show that any homomorphic image of a quasi-catenary module is quasi-catenary. We prove that if M   is a module with following properties: (i) Every quasi-prime submodule of M has finite quasi-height;...

The dynamic simulation system of a pantograph and a catenary has been built by using the finite element method, in which the pantograph is equivalent to a threemass-damper-stiffness system and the catenary contains only cable and beam elements. Considering droppers as nonlinear elements only stressed by tension, a sliding contact model of the pantograph and catenary is coupled by penalty functi...

An ultrasonic planar horn with a Bézier profile is developed. The first longitudinal displacement mode of the horn is exploited for high displacement amplification in order to reduce the penetration force required to enter and cut materials. The displacement amplification and stress distribution characteristics of the Bézier horn and the commonly used catenary horn are examined. The penetration...

This study is concerned with vortex-induced vibration (VIV) of deepwater marine risers. Riser response measurements from model tests on a densely instrumented long, flexible riser in uniform and sheared currents offer an almost ideal set-up for our work. Our objectives are two-fold: (i) we use the measured data to describe complexities inherent in riser motions accompanying VIV; and (ii) we dis...

The aim of this paper is to present an automatic, image-based system for catenary maintenance, a novel application of machine vision which has no equivalent today. This study focuses on the detection of droppers in catenary staves. The system takes benefit from the fact that dropper location inside catenary staves follows mounting rules, an information that is integrated into a top-down approac...