ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Residual stress & Finite element method. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

Major Changes in Growth Rate and Growth Variability of Beech (Fagus sylvatica L.) Related to Soil Alteration and Climate Change in Belgium

Abstract: Global change—particularly climate change, forest management, and atmospheric deposition—has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth (Fagus sylvatica L.) were investigated for the past 80 years in Belgium, using non-linear mixed effects models on ring-width chronologies of 149 mature and dominant beech trees (87–186 years old). The effects of the developmental stage (i.e., increasing tree size) were filtered out in order to focus on time-dependent growth changes. Beech radial growth was divided into a low-frequency signal (=growth rate), mainly influenced by forest management and atmospheric deposition, and into a high-frequency variability (≈mean sensitivity), mainly influenced by climate change. Between 1930 and 2008, major long-term and time-dependent changes were highlighted. The beech growth rate has decreased by about 38% since the 1950–1960s, and growth variability has increased by about 45% since the 1970–1980s. Our results indicate that (1) before the 1980s, beech growth rate was not predominantly impacted by climate change but rather by soil alteration (i.e., soil compaction and/or nitrogen deposition); and (2) since the 1980s, climate change induced more frequent and intense yearly growth reductions that amplified the growth rate decrease. The highlighted changes were similar in the two ecoregions of Belgium, although more pronounced in the lowlands than in the uplands.

Superconductivity and the Van Hove Scenario

Abstract: We give a review of the role of the Van Hove singularities in superconductivity. Van Hove singularities (VHs) are a general feature of low-dimensional systems. They appear as divergences of the electronic density of states (DOS). Jacques Friedel and Jacques Labbe were the first to propose this scenario for the A15 compounds. In NbTi, for example, Nb chains give a quasi-1D electronic structure for the d-band, leading to a VHs. They developed this model and explained the high T C and the many structural transformations occurring in these compounds. This model was later applied by Jacques Labbe and Julien Bok to the cuprates and developed by Jacqueline Bouvier and Julien Bok. The high T C superconductors cuprates are quasi-bidimensional (2D) and thus lead to the existence of Van Hove singularities in the band structure. The presence of VHs near the Fermi level in the cuprates is now well established. In this context we show that many physical properties of these materials can be explained, in particular the high critical temperature T C, the anomalous isotope effect, the superconducting gap and its anisotropy, and the marginal Fermi liquid properties, they studied these properties in the optimum and overdoped regime. These compounds present a topological transition for a critical hole doping p≈0.21 hole per CuO2 plane.

Emotion and interface design

Abstract: Usability has become a major notion for the conception and the evaluation of human-computer interactions. In order to push forward the quality of use, new areas of research are to be explored, and the question of end-users' emotions has become preponderant. Our view is to contribute to better ways to design and evaluate interfaces, by measuring the emotional impact of specific design strategies. In this paper, we discuss of emotional measurement methods which would fit the requirements of an interface use experience. Thus, we combine synchronous./asynchronous, objective/subjective complementary measures.

Useful Remarks To Reduce the Experimental Information Required To Determine the Equilibrium Water Content of Gas Near and Inside Gas Hydrate or Ice Formation Regions

Abstract: Experimental data regarding the water content of gases at low temperatures, especially near and inside the gas hydrate or ice formation regions, are rare and scarce. This is partly due to the fact that the water content is very low under these conditions and, hence, is generally difficult to measure. Furthermore, reaching equilibrium at low temperatures is a time-consuming process. In this communication, we present useful remarks to reduce the amount of experimental information required to determine the water content of a gas in equilibrium with a condensate, gas hydrate, or ice. The need for measuring the water content of a gas phase in equilibrium with a liquid water phase for tuning interaction parameters between water and gaseous component in an equation of statenamely, the Valderrama modification of the Patel−Teja equation of statealong with non-density-dependent mixing rules, is first examined. It is shown that the use of experimental data on the solubility of the gas in the liquid water phase can l...

A novel model for the integrated planning of part quality inspection and preventive maintenance in a linear-deteriorating serial multi-stage manufacturing system

Abstract: This paper presents a mixed-integer linear mathematical programming model for the integrated planning problem of the part quality inspection and preventive maintenance activities in serial multi-stage manufacturing system. The model concurrently determines the right time and place for performing the above-mentioned activities while the production stages are linearly deteriorating. These two decisions are made while the model is to minimize the total cost including the production, maintenance, inspection, scrap, replacement, and the penalty of shipped defective items to customer(s). A numerical example and a real case study are investigated to validate and verify the proposed model. The results show that the determination of inspection locations along a manufacturing line in different periods of time regarding the impact of preventive maintenance activities on defective production probability results in a more efficient manufacturing system.