Life cycle performance assessment tool development and application with a focus on maintenance aspects

Ships are among the most complex systems in the world. The always increasing interest in environmental aspects, the evolution of technologies and the introduction of new rule constraints in the maritime field have compelled the innovation of the ship design approach. At an early design stage, there is the need to compare different design solutions, also in terms of environmental performance, building and operative costs over the whole ship life cycle. In this context, the Life Cycle Performance Assessment (LCPA) tool allows an integrated design approach merging the evaluation of both costs and environmental performances on a comparative basis, among different design solutions. Starting from the first tool release, this work aims to focus on the maintenance of the propulsion system, developing a flexible calculation method for maintenance costs prediction, based on the ship operational profiles and the selected technical solution. After the improvement, the whole LCPA tool has been applied on a research vessel to evaluate, among different propulsion layout solutions, the one with the more advantageous performance in terms of costs during the whole vessel operating life. The identification of the best design solution is strictly dependent on the selection criterion and the point of view of the interested parties using the LCPA tool, e.g., the shipbuilder or the ship-owner

A historical analysis of herpes simplex virus promoter activation in vivo reveals distinct populations of latently infected neurones

Herpes simplex virus type 1 (HSV-1) has the capacity to establish a life-long latent infection in sensory neurones and also to periodically reactivate from these cells. Since mutant viruses defective for immediate-early (IE) expression retain the capacity for latency establishment it is widely assumed that latency is the consequence of a block in IE gene expression. However, it is not clear whether viral gene expression can precede latency establishment following wild-type virus infection. In order to address this question we have utilized a reporter mouse model system to facilitate a historical analysis of viral promoter activation in vivo. This system utilizes recombinant viruses expressing Cre recombinase under the control of different viral promoters and the Cre reporter mouse strain ROSA26R. In this model, viral promoter-driven Cre recombinase mediates a permanent genetic change, resulting in reporter gene activation and permanent marking of latently infected cells. The analyses of HSV-1 recombinants containing human cytomegalovirus major immediate-early, ICP0, gC or latency-associated transcript promoters linked to Cre recombinase in this system have revealed the existence of a population of neurones that have experienced IE promoter activation prior to the establishment of latency

Life Cycle Ship Performance Assessment (Lcpa): A Blended Formulation Between Costs And Environmental Aspects For Early Design Stage

BACKGROUND: In ship design, since the early stage, there is an increasing need to compare different design solutions analysing ship performances along the whole life-cycle frame, not only from the economical point of view, but also in terms of the environmental aspects. OBJECTIVE: To this aim, an approach is proposed to carry out the assessment of both cost and environmental performances on a comparative basis, among different ship design solutions. METHOD: A blended formulation between Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) is developed, with the option nevertheless to keep also each selected Key Performance Indicator (KPI) as a separated source of information. RESULTS: Significant KPIs are specifically identified and discussed; then a formulation is proposed for a comprehensive evaluation by means of a single index of Life Cycle Performance Assessment (LCPA). The harmonized formulation allows a rationally based comparison between projects and solutions, giving a weight to each selected KPI according to priorities of designers and ship wners/operators. A Ship Breakdown Structure has been developed to link ship design parameters with calculation of KPIs. Though the end of life is an essential phase to be accounted for in a life cycle evaluation, the practical approach presented in this paper is limited to Design/Construction and Operations. Decommissioning issues have been postponed to a future activity, keeping in mind that the topic is very much related to owners company policy and strongly dependant on details not available yet in the conceptual ship design phase. CONCLUSIONS: The decision-making activity during the ship design process needs to be supported by quantitative evaluations, properly projected over the whole ship lifetime range. In the paper, the structure of a bottom up procedure is proposed, starting from low level information and data (e.g. ship characteristics and operational profile) and arriving to a single parameter (LCPA index), by means of selected KPIs and their linear combination. Indeed, one of the great challenges is the availability and selection of appropriate data, needed to quantify KPIs during the design stage. The approach has been implemented and applied to a Ro-Ro passenger ship in order to verify and validate the LCPA tool structure and its reliability