Coefficient identification for ship manoeuvring simulation model based on optimization techniques

The frequency of ship grounding and collisions led to model the various factors involved during the course of a maneuvering ship. Among these factors are the ship hydrodynamic forces, the ship propulsion forces and forces due to the environmental conditions and the effects of confined water. This paper presents an approach for the identification of coefficients for a free-running ship. We elaborated a ship manoeuvring simulation model with a numerical procedure based on the coupling of optimization techniques and a ship motion simulation model. To identify the hydrodynamic coefficients, an automatic approach is proposed with two main steps: firstly, a sensitivity analysis to identify the most sensitive coefficients; secondly, optimization techniques to calculate their optimal value. Our model has been validated by using experimental data of Esso Bernicia Tanker (190000dwt) for the Turning Circle Test

Proton exchange membrane fuel cell operation and degradation in short-circuit.

International audienceThis paper presents an experimental study dealing with operation and degradation during an electrical short circuit of a proton exchange membrane fuel cell stack. The physical quantities in the fuel cell (electrical voltage and current, gas stoichiometry, pressures, temperatures and gas humidity) are studied before, during and after the failure. After a short circuit occurs, a high peak of current appears but decreases to stabilize in a much lower value. The voltage drops in all the cells and even some cells presents reversal potentials. The degradation is quantified by using electrochemical impedance spectroscopy

Children of Prisoners: Their Situation and Role in Long-Term Crime Prevention

Studies suggest that maintaining family ties can help reduce the likelihood of reoffending, and that while parental imprisonment can increase a child’s likelihood to offend, positive responses to the situation can aid the children’s well-being, attitude and attainment. Drawing on findings from the recently completed EU-funded COPING Project on the mental health of children of prisoners, this chapter explores the factors that aid a child’s ability to cope with parental imprisonment and the actions that different stakeholders can take to support them. It identifies some of the mental health impacts at different stages of parental imprisonment, the roles played by non-imprisoned parents/carers and by schools, and suggests options for further clarifying the factors that help and hinder children of prisoners in the short and long term

A Comparison between CG and PSO Algorithms for the Design of a PM Motor for Fuel Cell Ancillaries

Abstract — This paper deals with the design of a 500W permanent magnet (PM) machine used to drive the air-compressor of a 5kW fuel cell (FC). The authors focus on the optimization of the PM motor efficiency/mass/efficiency-mass in order to minimize the energy consumption of the air-compressor which can represent up to 30 % of the electrical energy delivered by the FC. The aim of this paper is to compare two types o

Coefficients identification for ship manoeuvring simulation based on optimization techniques

The frequency of ship grounding and collisions led to model the various factors involved during the course of a maneuvering ship. In this paper we present a numerical procedure to identify the hydrodynamic coefficients for a free-running ship by coupling the ship motion model and the optimization techniques. To accurate modeling of hydrodynamic parameters, a sensitivity analysis is first performed to identify the most sensitive factors. Then, optimization techniques are used to compute their optimal value. The model has been validated by using experimental data of Esso Bernicia Tanker (190000dwt) for the Turning Circle and Zigzag tests. The results show that the ship trajectories can be accurately predicted using a computationally efficient optimisation-based method for parameter identification procedure. Comparisons between experimental and computed ship trajectories show that the root-mean-square deviation (RMSD) decreased from 68.0m to 5.8m for Turning Circle test, and decreased from 17.3degs to 5.8degs for Zigzag test

Application of dynamic programming to optimal energy management of grid-independent hybrid railcars

In this paper, a dynamic programming-based optimization analysis is performed to quantitatively assess the energy-saving potential associated to the battery hybridization of railcars, which is nowadays regarded as a high-potential solution to reduce the greenhouse-gas impact of regional trains. A computationally effective longitudinal model is first developed, starting from an available energetic macroscopic representation modeling tool. The resulting simplified railcar model was first integrated with a battery state of charge simulator and then embedded within a fast constrained optimization algorithm. The optimization outcomes, reachable within reasonable timeframe and considering cost-effective hybridization scenarios, are highly informative for train manufacturers and operators interested in substantial hybridization of railcars. Particularly, fuel savings as high as 18% can be achieved with respect to the current diesel-powered trains. As a consequence, useful design and control guidelines are made available, considering both retrofitting or replacing the existing railway systems (particularly focusing on regional trains), while coping with capital and operating costs, safety, and traffic constraints

Experimental methods for the diagnosis of PEMFC stacks, Workshop

International audienc

Early warning and mass evacuation in coastal cities

The FP7 Theseus research project (2009\u20132013) aims to develop and assess innovative technologies and methodologies for coastal protection against erosion, flooding and environmental damages. While protection structures may help to reduce the level of hazard and the expected degree of loss, some danger of technical failures or human errors will always remain. For extreme events, the implementation of non-structural measures as early warning systems and disaster management practices is required to ensure the protection of population. During Theseus, a methodology for helping the local authorities to prepare an action plan in case of coastal flooding was developed and tested on the estuary of Gironde in France. The methodology builds over the return of experience from past events and tries to clearly identify all the stages of an evacuation and the thinking process that can lead to a robust evacuation plan. It relies on a conceptual framework \u2013 SADT \u2013 which helps to understand how data should be processed from its collection to its use in the plan. The risk scenarios were calculated for current and future conditions of the XXIst century, taking into account the effects of climate change. The methodology is supported by the OSIRIS software, prototyped during the FP5 eponymous project and later distributed by CETMEF and the French basin authorities of Loire and Meuse. The methodology for the preparation of evacuation plans was applied on a pilot city of Theseus, Bordeaux on the estuary of Gironde (France), and the software used to calculate evacuation times was tried out on Cesenatico near the Adriatic coast (Italy). This comparison verified the replicability of methodological guidelines in two different European contexts. The cultural and organizational differences and the different number of people involved underlined strong questions to be addressed when applying them. In order to assess the efficiency of an evacuation strategy and to compute the number of people successfully evacuated over time, a macroscopic model (not representing each individual vehicle but only flows of vehicles in congestion points) for the simulation of traffic congestion was used, based on the work of the University of Twente, Rijkswaterstaat and INFRAM. This model will be integrated in the Theseus decision support system for helping coastal managers to select their strategy for risk mitigation

Experimental methods for the diagnosis of PEMFC stacks, Workshop

International audienc

Study of temperature, air dew point temperature and reactant flow effects on PEMFC performances using electrochemical spectroscopy and voltammetry techniques

International audienc