Evidence for an endogenous rebound effect impacting long-run car use elasticity to fuel price

This paper presents a structural equation model of household fleet fuel efficiency and car use. It allows to weigh the contribution of car equipment changes and car use adjustments to the price elasticity of household demand for fuel. This model is implemented using a panel dataset of 322 households that were present in each annual wave of the French Car Fleet survey from 1999 to 2007. The longitudinal dimension of this dataset enables to assess the short and long-run adjustments at the household level over a period of fuel price increase. The estimated price elasticities of the demand for fuel are fully consistent with the literature: -0.30 in the short run and -0.76 in the long run. Regarding car use elasticities, accounting for an endogenous rebound effect allowed a striking finding: the sensitivity of household car use to fuel price changes is lower on the long run than on the short run. This paper thus not only provides the latest estimations of elasticities for France, in the early 2000's, it also shows that, on the long run, French households have managed to mitigate the impact of increasing fuel prices on their car mobility by using more fuel efficient cars.Elasticity, Fuel Price, Rebound effect, Energy consumption, Energy efficiency, Car use, Household, Panel data

Trends in the French commercial farm population

Knowledge and projection of farm numbers and the structure of their population is an important issue for agricultural economists and policy makers. Although Markov chain models have enjoyed decades of popularity in forecasting total farm numbers, they generally fail to provide a detailed insight of the farm population’s structure; to overcome this caveat we estimate a parametric distribution of the utilized agricultural area of French commercial farms. Our method provides detailed information on the structure of the population and accounts for the specificity of off-land farming. We also model the influence of variables such as the farm’s legal status, type of farming and farm holder’s age. The estimation leads to a relevant description of the entire population of professional farm. When compared with the 2005 Farm Structure Survey data, our simulations based on FADN data display a close match across a number of key variables.farm structures, farm size distribution, maximum likelihood and simulation

Water nanoelectrolysis: A simple model

A simple model of water nanoelectrolysis-defined as the nanolocalization at a single point of any electrolysis phenomenon-is presented. It is based on the electron tunneling assisted by the electric field through the thin film of water molecules ($\sim$0.3 nm thick) at the surface of a tip-shaped nanoelectrode (micrometric to nanometric curvature radius at the apex). By applying, e.g., an electric potential V 1 during a finite time t 1 , and then the potential --V 1 during the same time t 1 , we show that there are three distinct regions in the plane (t 1 , V 1): one for the nanolocalization (at the apex of the nanoelectrode) of the electrolysis oxidation reaction, the second one for the nanolocalization of the reduction reaction, and the third one for the nanolocalization of the production of bubbles. These parameters t 1 and V 1 completely control the time at which the electrolysis reaction (of oxidation or reduction) begins, the duration of this reaction, the electrolysis current intensity (i.e., the tunneling current), the number of produced O 2 or H 2 molecules, and the radius of the nanolocalized bubbles. The model is in good agreement with our experiments

Trends in the French commercial farm population

.Knowledge and projection of farm numbers and the structure of their population is an important issue for agricultural economists and policy makers. Although Markov chain models have enjoyed decades of popularity in forecasting total farm numbers, they generally fail to provide a detailed insight of the farm population’s structure; to overcome this caveat we estimate a parametric distribution of the utilized agricultural area of French commercial farms. Our method provides detailed information on the structure of the population and accounts for the specificity of off-land farming. We also model the influence of variables such as the farm’s legal status, type of farming and farm holder’s age. The estimation leads to a relevant description of the entire population of professional farm. When compared with the 2005 Farm Structure Survey data, our simulations based on FADN data display a close match across a number of key variables.farm structures, farm size distribution, maximum likelihood, simulation

Addiction to car use and dynamic elasticity measures in France

This article presents a microeconometric analysis of the annual mileage travelled by French households with their personal cars, defining their automobility. To feature car use dependence, the rational addiction model of Becker et al. (1994) is applied on a panel dataset, drawn from the French "Car Fleet" survey over the period 1999-2001. Importantly, the estimates show that the assumption of addiction to car use cannot be rejected. Furthermore, the model yields realistic kilometric-price and income elasticities of household automobility, for both the short and the long runs.Transportation ; Car use ; Consumption ; Addiction ; Panel ; GMM

A novel numerical mechanical model for the stress–strain distribution in superconducting cable-in-conduit conductors \ud

Besides the temperature and magnetic field, the strain and stress state of the superconducting Nb3Sn wires in multi-stage twisted cable-in-conduit conductors (CICCs), as applied in ITER or high field magnets, strongly influence their transport properties. For an accurate quantitative prediction of the performance and a proper understanding of the underlying phenomena, a detailed analysis of the strain distribution along all individual wires is required. For this, the thermal contraction of the different components and the huge electromagnetic forces imposing bending and contact deformation must be taken into account, following the complex strand pattern and mutual interaction by contacts from surrounding strands. In this paper, we describe a numerical model for a superconducting cable, which can simulate the strain and stress states of all single wires including interstrand contact force and associated deformation. The strands in the cable can be all similar (Nb3Sn/Cu) or with the inclusion of different strand materials for protection (Cu, Glidcop).\ud \ud The simulation results are essential for the analysis and conductor design optimization from cabling to final magnet operation conditions. Comparisons are presented concerning the influence of the sequential cable twist pitches and the inclusion of copper strands on the mechanical properties and thus on the eventual strain distribution in the Nb3Sn filaments when subjected to electromagnetic forces, axial force and twist moment. Recommendations are given for conductor design improvements. \ud \ud \u

Plasma cleaning of ITER first mirrors in magnetic field

To avoid reflectivity losses in ITER optical diagnostic systems, plasma sputtering of metallic First Mirrors is foreseen in order to remove deposits coming from the main wall (mainly beryllium and tungsten). Therefore plasma cleaning has to work on large mirrors (up to a size of 200*300 mm) and under the influence of strong magnetic fields (several Tesla). This work presents the results of plasma cleaning of aluminium and aluminium oxide (used as beryllium proxy) deposited on molybdenum mirrors. Using radio frequency (13.56 MHz) argon plasma, the removal of a 260 nm mixed aluminium/aluminium oxide film deposited by magnetron sputtering on a mirror (98 mm diameter) was demonstrated. 50 nm of pure aluminium oxide were removed from test mirrors (25 mm diameter) in a magnetic field of 0.35 T for various angles between the field lines and the mirrors surfaces. The cleaning efficiency was evaluated by performing reflectivity measurements, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy.Comment: 5 pages, 6 figures and 1 table. Results presented on the 21st Plasma Surface Interaction conference held in Kanazawa Japan, May 201

Market-making, inventories and martingale pricing

Working Paper du GATE 2002-03We discuss Shen and Starr(2002) results and show that the bid-ask spread of a monopolistic market-marker doesn't depend on his inventory when he posts ''martingale prices '' in an inventory model with random volumes and an unknown direction of trade.Nous discutons les résultats de Shen et Starr (2002) et montrons que la fourchette de prix de réservation d'un teneur de marché ne dépend pas de son inventaire lorsque celui-ci fixe un prix suivant une martingale dans un modèle d'inventaire avec volumes aléatoires et direction de l'échange inconnnue