Pulsating fronts for bistable on average reaction-diffusion equations in a time periodic environment

This paper is devoted to reaction-diffusion equations with bistable nonlinearities depending periodically on time. These equations admit two linearly stable states. However, the reaction terms may not be bistable at every time. These may well be a periodic combination of standard bistable and monostable nonlinearities. We are interested in a particular class of solutions, namely pulsating fronts. We prove the existence of such solutions in the case of small time periods of the nonlinearity and in the case of small perturbations of a nonlinearity for which we know there exist pulsating fronts. We also study uniqueness, monotonicity and stability of pulsating fronts

Fisher-KPP equations and applications to a model in medical sciences

This paper is devoted to a class of reaction-diffusion equations with nonlinearities depending on time modeling a cancerous process with chemotherapy. We begin by considering nonlinearities periodic in time. For these functions, we investigate equilibrium states, and we deduce the large time behavior of the solutions, spreading properties and the existence of pulsating fronts. Next, we study nonlinearities asymptotically periodic in time with perturbation. We show that the large time behavior and the spreading properties can still be determined in this case

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A Plant Life Management Model as Support to Plant Life Extension Programs of Nuclear Installations - Effective Integration of the Safety Programs into an Overall Optimization of the Operating Costs

Main objectives of this report, as outcome of the research activities carried out in 2008 and in previous years by the research network SENUF, are the following: 1. To collect the experience of the European Countries in the field of Plant Life Management (PLIM) and Plant Life Extension (PLEX), seen as two crucial programs in safety and cost optimisation at operating plants 2. To settle a model for PLIM also suitable to support a PLEX program, tailored to the European market 3. To validate the proposed model against the European practice. The basic goal of PLiM, as it is defined in this research, is to satisfy requirements for safe, possibly long-term, supplies of electricity in an economically competitive way. The basic goal of the operating companies is to operate as long as economically reasonable from the safety point of view. PLiM is a management tool for doing that. Therefore PLiM is a system of programmes and procedures developed in many Countries, with some differences due to the national framework, to satisfy safety requirements for safe operation and for power production in a competitive way in a time frame which is rational from both the technical and economical point of view. PLiM programmes address both technical and economic issues, as well as knowledge management issues. This report makes reference to the first part of this study that was completed in 2007, when a PLIM model was proposed and validated at real Nuclear Power Plants. This report adds some important contributions in three areas: definition of the PLIM scope, review of the Ageing Management Program for selected structures, management of contractors and strategic alliances. These contributions were selected after a thorough analysis of the European best practice, also with the contribution of the SENUF network Members. The validation of the proposed PLIM model, including the improvements described in this report, represents only the first step of a more ambitious program of validation/improvement that will be implemented in the course of 2009.JRC.F.5-Safety of present nuclear reactor

Malignant Hyperthermia

Although very rare, occurring one out of every 100,000 anesthesia cases, malignant hyperthermia is a hypermetabolic disorder that anesthesia providers screen and interrogate patients prior to every case they are administering anesthesia. Many research studies about anesthesia induced malignant hyperthermia have explored new methods of testing for the genetic susceptibility for malignant hyperthermia and into hospital based protocols when a patient starts to show the signs and symptoms of the metabolic disorder. This new knowledge and understanding has decreased patient mortality of anesthesia induced malignant hyperthermia from eighty percent to five percent over the past three decades (Rosenberg et al, 2007)

Nauseated, Anguished and Ashamed: Where Did Sartre Go Wrong?

This thesis examines Jean-Paul Sartre’s ontology and argues that his conception of consciousness as individuated nothingness is responsible for the discontented human condition he describes. It further argues that this ontology is at variance with our experience, and as such the human condition is not inevitably unhappy. Instead, a phenomenological description of consciousness as transpersonal and full is advanced. A transpersonal ontology of consciousness asserts that consciousnesses are not entirely individuated from one another, but constitutively constructed by “other” consciousnesses, which renders them full. Consciousness as transpersonal leads to a reconceptualization of the subject-other relationship as an I-as-other-other-as-me relationship. Transpersonal consciousness is then employed to re-interpret Sartre’s discontents, and largely resolves the unhappy features of the human condition by leading to the possibility of peaceful relationships with ourselves and harmonious relationships with others

A Plant Life Management Model Including Optimized MS&I Program - Safety and Economic Issues

This report collects the experience of the European Countries in the field of Plant Life Management (PLIM) and maintenance optimisation, as a background for the development of a new PLIM models, suitable for the European framework. The research highlights the the basic goal of PLiM in terms of support to a safe long-term supply of electricity in an economically competitive way. A PLIM model is proposed, validated with the experience of the SENUF research network members and with the essential contribution of managers and staff of a selected nuclear plant. The model addresses both technical and economic issues, as well as organizational and knowledge management issues and is now open for a broader validation by the research and engineering communities, to be carried out in the coming research steps.JRC.F.5-Nuclear operation safet

Safety Aspects of Long Term Operation of Nuclear Power Plants

In the last years many Member States started a programme to assess the possibility for a Long Term Operation of their older nuclear power plants. These programs follow different approaches, being intrinsically dependent on the national regulatory framework and technical tradition. Typical safety assessment processes such as the Periodic Safety Review can be used as a framework for the preparation of long-term operation. Also the Licence Renewal based on the review of ageing management programs in context with other regulatory tools as the regular updating of the Safety Analysis Report could be used to ensure a safe long-term operation. The analysis of the practice in countries operating NPPs suggested that despite the differences related to the regulatory process, the main components of the programs and their basic technical tasks are shared among most of the countries. This paper aims at identifying the technical aspects more directly affecting the decision for a long-term safe operation of a nuclear facility, independently from their licensing framework. The paper includes an analysis of the safety implications of a program for preparation of long- term operation of NPPs, with reference to the available IAEA documents and experience in the review of national programs. The program running at Paks NPP Hungary represents one of the most recent experiences in the field. It is presented in the paper as an example of application of general safety principles to a real case, with proposals of solutions for practical problems common to many similar plants

The Concept of the Machining Surface in 5-Axis Milling of Free-form Surfaces

International audienceThe concept of the machining surface (MS) is a new approach to the process of design and manufacturing of free form surfaces. The machining surface is the surface representation of the tool path, integrating functional design specifications and machining constraints. By definition, the machining surface is a surface including all the information necessary for the driving of the tool, so that the envelope surface of the tool movement sweeping the MS gives the expected free-form. In this paper, we study the building of the MS for 5-axis end milling with usual cutting tools, ball, flat and filleted endmill. We make so that the design and manufacturing constraints taken into account by the machining surface are completely uncoupled within the MS.Le concept de la surface d'usinage apporte une évolution dans le processus de réalisation des pièces de forme gauche au ni-veau de la conception et de la fabrication. La surface d'usinage est une représentation surfacique du trajet de l'outil intégrant les contrain-tes fonctionnelles de conception ainsi que les contraintes technologiques de fabrication. Par définition, la surface d'usinage guide un point fixe de l'outil de telle sorte que la surface enveloppe du mouvement de l'outil soit la surface attendue. Nous présentons dans cet article comment se construit la surface d'usinage pour le fraisage à cinq axes en bout avec les outils de coupe couramment utilisés. Nous faisons en sorte que les aspects conception et fabrication pris en compte par la surface d'usinage soient totalement découplés afin de conserver ces activités indépendantes