Abstract

Measurement of the structure-borne sound energy flow through pipes has been studied for the purpose of transmission path ranking. This paper describes the measuring methods for frequencies below the cut-off frequency of the n = 2 shell mode. The methods show a strong analogy with the two-microphone cross-spectral density method for airborne sound intensity measurements. Experiments on two lightly damped pipe sections of a cooling water circuit are used to illustrate some practical measuring aspects and some procedures for error analysis. Reasonably accurate measurements appear feasible, provided high quality instrumentation is used and the various wave types are separated carefully.

Abstract

The typical voyage of a barge transporting maritime containers inland, consists of visiting a set of terminals where loading/unloading operations occur. The required stowage plans must meet stability requirements during all transport phases and avoid costly re-handling operations. In this paper, we formalize this problem and consider a typical dry-port transport system. We propose a comprehensive mathematical model that seeks to maximize stowed containers. To solve it, we develop a hybrid metaheuristic approach, based on local search and an industrial solver. Numerical experiments, based on real-world data, provide insights into the performances of the proposed framework and current stowage practices.