Seatech

In a stationary ergodic process, clustering is defined as the tendency of events to appear in series of increased frequency separated by longer breaks. Such behavior, contradicting the theoretical "unbiased behavior" with exponential distribution of the gaps between appearances, is commonly observed in experimental processes and often difficult to explain. In the last section we relate one such empirical example of clustering, in the area of marine technology. In the theoretical part of the paper we prove, using ergodic theory and the notion of category, that clustering (even very strong) is in fact typical for "rare events" defined as long cylinder sets in processes generated by a finite partition of an arbitrary (infinite aperiodic) ergodic measure preserving transformation.

We focus in this paper on the contribution of a subsystem to the environmental impact of a system. In this way we propose to explore some limits related to Life Cycle Assessment (LCA), in particular the consideration of the use phase specificities (for example lifetime, technology or energy mix). Two cases studies concerning AREVA T&D's aluminium electrolysis conversion substations are proposed to illustrate these problems. The first one considers the environmental contribution of a transformer to the electrical substation, whereas the second one studies the contribution of the substation to primary aluminium production. We show that the context specificities of a product should be taken into account in order to assess its real environmental impacts. To ignore them can lead to false conclusions, what is essential to avoid when a company wants to define its eco-design strategy.

This paper is concerned with the environment integration in product design. Declarations about environment integration are numerous but it is still difficult today to assess products environmental qualities. Without shunting the question of available resources facing the problems to solve, we are proposing an environment integration approach based on a knowledge learning process. This approach was build to help design engineers to appropriate the new field of environment. To do that we will develop a learning driving tool for which we will explain the construction and the use with concrete examples.

The integration of environmental concerns into the product design process is not trivial when dealing with complex industrial systems. Actually, environmental assessment methodologies like Life Cycle Assessments (LCA) reach, in this case, methodological and organisational limits. More generally, the complexity inherent in the design process may put off eco-design initiatives from a lack of organisational management, methods and tools. In this paper, we propose a project management methodology to facilitate the integration of eco-design into the design process of complex industrial systems. This methodology is based on continuous improvement and a DMAIC process. It is then structured around precise team definition, precise milestones, deliverables and phases. A first stage ensures a reliable environmental assessment of the full system and the identification of environmental improvement projects. A second stage allows the independent execution of the most promising improvement projects. A first application is proposed on the Alstom Grid AC/DC conversion substations for the aluminium industry. A Life Cycle Assessment has been performed with limited resources and has provided rich findings and promising perspectives. It shows in particular that the best environmental configuration of such a complex industrial system depends on external parameters like the implantation site.