How do solar photovoltaic feed-in tariffs interact with solar panel and silicon prices? An empirical study

Preferential feed-in tariffs (FITs) for solar generated electricity increases the demand for solar photovoltaic systems. They can thus induce price to increase, creating the potential for PV systems producers to collect rents. This paper analyses the interactions between feed-in tariffs, silicon prices and module prices, using weekly price data and FIT values in Germany, Italy, Spain, and France from January 2005 to May 2012. Relying methodologically on the Granger causality tests applied to vector autoregressive models, we show that since the end of the period of silicon shortage in 2009, module price variations cause changes in FITs, and not the reverse. This is good news as it suggests that the regulators have been able to prevent FITs to inflate module prices

Solving Linear Constraints in Elementary Abelian p-Groups of Symmetries

Symmetries occur naturally in CSP or SAT problems and are not very difficult to discover, but using them to prune the search space tends to be very challenging. Indeed, this usually requires finding specific elements in a group of symmetries that can be huge, and the problem of their very existence is NP-hard. We formulate such an existence problem as a constraint problem on one variable (the symmetry to be used) ranging over a group, and try to find restrictions that may be solved in polynomial time. By considering a simple form of constraints (restricted by a cardinality k) and the class of groups that have the structure of Fp-vector spaces, we propose a partial algorithm based on linear algebra. This polynomial algorithm always applies when k=p=2, but may fail otherwise as we prove the problem to be NP-hard for all other values of k and p. Experiments show that this approach though restricted should allow for an efficient use of at least some groups of symmetries. We conclude with a few directions to be explored to efficiently solve this problem on the general case.Comment: 18 page

Innovation and international technology transfer: The case of the Chinese photovoltaic industry

CERNA WORKING PAPER SERIES 2010-12International audienceChina is the largest solar photovoltaic cell producer in the world, with more than one third of worldwide production in 2008, exporting more than 95 percent of what it produces. The purpose of this paper is to understand the drivers of this success and its limits, with a particular emphasis on the role of technology transfers and innovation. Our analysis combines a review of international patent data at a detailed technology level with field interviews of ten Chinese PV companies. We show that Chinese producers have acquired the technologies and skills necessary to produce PV products through two main channels: the purchasing of manufacturing equipment in a competitive international market and the recruitment of skilled executives from the Chinese diaspora who built pioneer PV firms. The success of these firms in their market is, however, not reflected in their performance in terms of innovation. Rather, patent data rather highlight a policy-driven effort to catch up in critical technological areas

Arrondissements de Cahors, Figeac et Gourdon

Lien Atlas (MCC) :http://atlas.patrimoines.culture.fr/atlas/trunk/index.php?ap_theme=DOM_2.01.02&ap_bbox=1.373;44.401;1.505;44.512 Dans un but de complément à la carte archéologique régionale, notre travail de prospection sur cette zone s’est poursuivi en 2013, il consiste à positionner sur feuilles cadastrales, aussi précisément que possible, dolmens, tumuli et autres sites anthropiques, ce qui permet ensuite d’en déterminer les coordonnées. Notre base de travail restant l'inventaire des még..

Innovation and international technology transfer: The case of the Chinese photovoltaic industry

China is the largest solar photovoltaic cell producer in the world, with more than one third of worldwide production in 2008, exporting more than 95 percent of what it produces. The purpose of this paper is to understand the drivers of this success and its limits, with a particular emphasis on the role of technology transfers and innovation. Our analysis combines a review of international patent data at a detailed technology level with field interviews of ten Chinese PV companies. We show that Chinese producers have acquired the technologies and skills necessary to produce PV products through two main channels: the purchasing of manufacturing equipment in a competitive international market and the recruitment of skilled executives from the Chinese diaspora who built pioneer PV firms. The success of these firms in their market is, however, not reflected in their performance in terms of innovation. Rather, patent data rather highlight a policy-driven effort to catch up in critical technological areas.Solar photovoltaic energy; technology diffusion; technology transfer; China

Fluctuation-induced first-order phase transition in Dzyaloshinskii-Moriya helimagnets

Two centuries of research on phase transitions have repeatedly highlighted the importance of critical fluctuations that abound in the vicinity of a critical point. They are at the origin of scaling laws obeyed by thermodynamic observables close to second-order phase transitions resulting in the concept of universality classes, that is of paramount importance for the study of organizational principles of matter. Strikingly, in case such soft fluctuations are too abundant they may alter the nature of the phase transition profoundly; the system might evade the critical state altogether by undergoing a discontinuous first-order transition into the ordered phase. Fluctuation-induced first-order transitions have been discussed broadly and are germane for superconductors, liquid crystals, or phase transitions in the early universe, but clear experimental confirmations remain scarce. Our results from neutron scattering and thermodynamics on the model Dzyaloshinskii-Moriya (DM) helimagnet (HM) MnSi show that such a fluctuation-induced first-order transition is realized between its paramagnetic and HM state with remarkable agreement between experiment and a theory put forward by Brazovskii. While our study clarifies the nature of the HM phase transition in MnSi that has puzzled scientists for several decades, more importantly, our conclusions entirely based on symmetry arguments are also relevant for other DM-HMs with only weak cubic magnetic anisotropies. This is in particular noteworthy in light of a wide range of recent discoveries that show that DM helimagnetism is at the heart of problems such as topological magnetic order, multiferroics, and spintronics.Comment: 19 pages, 9 figures, 2 table

Inventaire des mégalithes

Date de l'opération : 1991 (PI) Inventeur(s) : Fayet de la Tour Alain du À la suite d'un projet d'aménagement de circuit touristique autour des dolmens de la commune de Foissac, Alain du Fayet de la Tour, a repris le recensement des mégalithes de cette zone occidentale de l'Aveyron, géographiquement rattachée au Quercy. Un précédent inventaire avait été réalisé une douzaine d'années auparavant (Clottes, Maurand, 1983) et il était intéressant d'effectuer un contrôle systématique de l'état de c..