Non-Equilibrium Statistical Mechanics of Anharmonic Chains Coupled to Two Heat Baths at Different Temperatures

We study the statistical mechanics of a finite-dimensional non-linear Hamiltonian system (a chain of anharmonic oscillators) coupled to two heat baths (described by wave equations). Assuming that the initial conditions of the heat baths are distributed according to the Gibbs measures at two different temperatures we study the dynamics of the oscillators. Under suitable assumptions on the potential and on the coupling between the chain and the heat baths, we prove the existence of an invariant measure for any temperature difference, i.e., we prove the existence of steady states. Furthermore, if the temperature difference is sufficiently small, we prove that the invariant measure is unique and mixing. In particular, we develop new techniques for proving the existence of invariant measures for random processes on a non-compact phase space. These techniques are based on an extension of the commutator method of H\"ormander used in the study of hypoelliptic differential operators.Comment: 43 page

Entropy Production in Non-Linear, Thermally Driven Hamiltonian Systems

We consider a finite chain of non-linear oscillators coupled at its ends to two infinite heat baths which are at different temperatures. Using our earlier results about the existence of a stationary state, we show rigorously that for arbitrary temperature differences and arbitrary couplings, such a system has a unique stationary state. (This extends our earlier results for small temperature differences.) In all these cases, any initial state will converge (at an unknown rate) to the stationary state. We show that this stationary state continually produces entropy. The rate of entropy production is strictly negative when the temperatures are unequal and is proportional to the mean energy flux through the system

The 'hidden hypothesis'- approach in evaluation methodology: The Swiss participation in the European INTERREG II- Programme

Regional development, and crossborder cooperation in particular, needs feedbacks on the impacts of public policies. Policy evaluation is one appropriate tool. The ?hidden hypothesis'- approach is characterized by two elements: (1) an emphasis on the invisible goals of an evaluated programme or instrument and (2) a strong orientation towards processes of learning and motivation with the actors involved. (1) The formulation of political programmes tends to integrate as much different interests as possible. Such goal-setting processes simplify political agreement. But to evaluate such programmes with all their different and partly conflicting goals creates problems. The quality of an evaluation cannot be better as the quality of the evaluated goals and conflicting goals lead straight forward to conflicting results. (2) Evaluating the results of a political programme is also confronted with problems of measurement. Evaluation methodology normally distinguishes output, impact and outcome of a programme or a project. In general it is very tricky to evaluate the outcome. Thus the presented approach of evaluation works with different logic. The approach aims at enabling the actors concerned to modify and rearrange their activities. The evaluator acts as moderator and gives inputs for the necessary learning processes. This approach can be used especially in intermediate evaluations and monitoring. The case of the Swiss participation to the European INTERREG II- Programme shows a great complexity concerning political goals and concerning the cooperation in a federalistic political structure. Therefore the casestudy is a good example to demonstrate the advantages of the approach: In 1992 the Swiss population voted against joining the European Economic Market Treaty. The narrow rejection by plebiscite lead to intense discussions about the national cohesion. Afterwards the federal strategy to move the country towards an European integration has been based on a piecemeal approach and small projects of crossborder micro-integration. As an important strategic policy instrument the Swiss government decided to contribute to the INTERREG II- Programme of crossborder cooperation with own ressources of co-financing. In this situation the system of goals connected with the participation in INTERREG II is very complex: The different explicite and implicite goals can be categorized by a double dichotomy: On the one hand the tension between the goal of European integration and the goal of (Swiss) regional development. On the other hand the tension between active policy steering and re-active coordinating. Both relationsships are overlapping and influence the administrative levels between central government and the single local project. To evaluate this policy is a work of great complexity. Key words: evaluation methodology, regional crossborder development, INTERREG, Switzerland

Production, by co-grinding in a media mill, of porous biodegradable polylactic acid-apatite composite materials for bone tissue engineering

This paper presents the results of a study of the production of porous biodegradable composite materials by co-grinding, followed by scaffolding. Dry powders of polylactic acid and nanocrystalline carbonated apatite, analogous to bone mineral were co-ground in a tumbling ball mill in order to disperse the mineral filler within the polymer. Porous scaffolds were then made by hot moulding the mixture of the two components along with a pore-forming agent which was subsequently eliminated by washing. The mechanical resistance of the scaffolds was evaluated in order to determine the best operating conditions to produce implants offering optimised properties for use as bone substitutes. It was shown that 30 wt.% of filler and 70 wt.% of pore-forming agent produce scaffolds which are sufficiently porous and resistan

Environmental Impact Assessment of Solid Polymer Electrolytes for Solid-State Lithium Batteries

Solid-state batteries play a pivotal role in the next-generation batteries as they satisfy the stringent safety requirements for stationary or electric vehicle applications. Notable efforts are devoted to the competitive design of solid polymer electrolytes (SPEs) acting as both the electrolyte and the separator. Although particular efforts to attain acceptable ionic conductivities and wide electrochemical stability widows are carried out, the environmental sustainability is largely neglected. To address this gap, here the cradle-to-gate environmental impacts of the most representative SPEs using life cycle assessment (LCA) are quantified. Raw material extraction and electrolyte fabrication are considered. Global warming potential values of 0.37–10.64 kg CO2 equiv. gelectrolyte −1 are achieved, where PEO/LiTFSI presents the lower environmental burdens. A minor role of the polymer fraction on the total impacts is observed, with a maximum CO2 footprint share of 0.61%. Following ecodesign approaches, a sensitivity analysis is performed to simulate industrial-scale fabrication processes and explore environmentally friendlier scenarios. The electrochemical performance of SPEs is further analyzed into Li/LiFePO4 solid lithium metal battery cell configuration. Overall, these results are aimed to guide the ecologically sustainable design of SPEs and facilitate the implementation of next-generation sustainable batteries.The authors gratefully acknowledge support from Siemens Gamesa (Students4Sustainability Grant) and 4GUNE (Clúster de Ingeniería, Ciencia y Tecnología de Euskadi). The authors are also grateful for the Open Access funding provided by the University of Basque Country (UPV/EHU)

The 'hidden hypothesis'- approach in evaluation methodology: The Swiss participation in the European INTERREG II- Programme

Regional development, and crossborder cooperation in particular, needs feedbacks on the impacts of public policies. Policy evaluation is one appropriate tool. The ?hidden hypothesis'- approach is characterized by two elements: (1) an emphasis on the invisible goals of an evaluated programme or instrument and (2) a strong orientation towards processes of learning and motivation with the actors involved. (1) The formulation of political programmes tends to integrate as much different interests as possible. Such goal-setting processes simplify political agreement. But to evaluate such programmes with all their different and partly conflicting goals creates problems. The quality of an evaluation cannot be better as the quality of the evaluated goals and conflicting goals lead straight forward to conflicting results. (2) Evaluating the results of a political programme is also confronted with problems of measurement. Evaluation methodology normally distinguishes output, impact and outcome of a programme or a project. In general it is very tricky to evaluate the outcome. Thus the presented approach of evaluation works with different logic. The approach aims at enabling the actors concerned to modify and rearrange their activities. The evaluator acts as moderator and gives inputs for the necessary learning processes. This approach can be used especially in intermediate evaluations and monitoring. The case of the Swiss participation to the European INTERREG II- Programme shows a great complexity concerning political goals and concerning the cooperation in a federalistic political structure. Therefore the casestudy is a good example to demonstrate the advantages of the approach: In 1992 the Swiss population voted against joining the European Economic Market Treaty. The narrow rejection by plebiscite lead to intense discussions about the national cohesion. Afterwards the federal strategy to move the country towards an European integration has been based on a piecemeal approach and small projects of crossborder micro-integration. As an important strategic policy instrument the Swiss government decided to contribute to the INTERREG II- Programme of crossborder cooperation with own ressources of co-financing. In this situation the system of goals connected with the participation in INTERREG II is very complex: The different explicite and implicite goals can be categorized by a double dichotomy: On the one hand the tension between the goal of European integration and the goal of (Swiss) regional development. On the other hand the tension between active policy steering and re-active coordinating. Both relationsships are overlapping and influence the administrative levels between central government and the single local project. To evaluate this policy is a work of great complexity. Key words: evaluation methodology, regional crossborder development, INTERREG, Switzerlan

Vieillir en ville ?

Les multiples stratégies élaborées pour accroître la durabilité des villes et des agglomérations font émerger aujourd’hui un consensus autour d’un certain nombre de principes, notamment la nécessité de limiter l’étalement urbain, d’intégrer les questions de mobilité à l’évolution de l’urbanisation, de promouvoir une certaine mixité fonctionnelle et sociale et de viser une qualité de vie accrue en milieu urbain