Ageing and relaxation times in disordered insulators

We focus on the slow relaxations observed in the conductance of disordered insulators at low temperature (especially granular aluminum films). They manifest themselves as a temporal logarithmic decrease of the conductance after a quench from high temperatures and the concomitant appearance of a field effect anomaly centered on the gate voltage maintained. We are first interested in ageing effects, i.e. the age dependence of the dynamical properties of the system. We stress that the formation of a second field effect anomaly at a different gate voltage is not a "history free" logarithmic (lnt) process, but departs from lnt in a way which encodes the system's age. The apparent relaxation time distribution extracted from the observed relaxations is thus not "constant" but evolves with time. We discuss what defines the age of the system and what external perturbation out of equilibrium does or does not rejuvenate it. We further discuss the problem of relaxation times and comment on the commonly used "two dip" experimental protocol aimed at extracting "characteristic times" for the glassy systems (granular aluminum, doped indium oxide...). We show that it is inoperable for systems like granular Al and probably highly doped InOx where it provides a trivial value only determined by the experimental protocol. But in cases where different values are obtained like in lightly doped InOx or some ultra thin metal films, potentially interesting information can be obtained, possibly about the "short time" dynamics of the different systems. Present ideas about the effect of doping on the glassiness of disordered insulators may also have to be reconsidered.Comment: to appear in the proceedings of the 14th International Conference on Transport and Interactions in Disordered Systems (TIDS14

pcolor in polar coordinates

polarPcolor aims to represent a pseudocolour plot in polar coordinates, with a radial grid to allow clear visualization of the data. It is well suited for Plan Position Indicator (PPI) scan for radar or lidar for example [1]. A similar function is available in ref. [2], which propose a visualization in 3D. References: [1] Cheynet, E., Jakobsen, J. B., Snæbjörnsson, J., Reuder, J., Kumer, V., & Svardal, B. (2017). Assessing the potential of a commercial pulsed lidar for wind characterisation at a bridge site. Journal of Wind Engineering and Industrial Aerodynamics, 161, 17-26. http://dx.doi.org/10.1016/j.jweia.2016.12.002 [2] http://www.mathworks.com/matlabcentral/fileexchange/13200-3d-polar-plo

Late Byzantine sigillographic evidence from Cappadocia: lead seals from Kırşehir with a unique overstruck example

International audienc

The COTUR project: remote sensing of offshore turbulence for wind energy application

The paper presents the measurement strategy and data set collected during the COTUR (COherence of TURbulence with lidars) campaign. This field experiment took place from February 2019 to April 2020 on the southwestern coast of Norway. The coherence quantifies the spatial correlation of eddies and is little known in the marine atmospheric boundary layer. The study was motivated by the need to better characterize the lateral coherence, which partly governs the dynamic wind load on multi-megawatt offshore wind turbines. During the COTUR campaign, the coherence was studied using land-based remote sensing technology. The instrument setup consisted of three long-range scanning Doppler wind lidars, one Doppler wind lidar profiler and one passive microwave radiometer. Both the WindScanner software and LidarPlanner software were used jointly to simultaneously orient the three scanner heads into the mean wind direction, which was provided by the lidar wind profiler. The radiometer instrument complemented these measurements by providing temperature and humidity profiles in the atmospheric boundary layer. The scanning beams were pointed slightly upwards to record turbulence characteristics both within and above the surface layer, providing further insight on the applicability of surface-layer scaling to model the turbulent wind load on offshore wind turbines. The preliminary results show limited variations of the lateral coherence with the scanning distance. A slight increase in the identified Davenport decay coefficient with the height is partly due to the limited pointing accuracy of the instruments. These results underline the importance of achieving pointing errors under 0.1∘ to study properly the lateral coherence of turbulence at scanning distances of several kilometres.publishedVersio

Seals of museums in eastern Turkey: Karaman, Nevsehir, Malatya, Maras | Sceaux des musées de la turquie orientale : Karaman, Nevşehir, Malatya, Maraş

Stemming from a survey program conducted by Esra Erdoğan in eastern Anatolia, this article presents the Byzantine lead seals housed in four Turkish museums : Malatya (formerly Melitene), Karaman (formerly Laranda), Kahramanmaraş (former Germanicea), and Nevşehir in Cappadocia. The interest in these collections is to gain new insight into the administrative organization of the Byzantine provinces established in these regions. All the seals examined are published here for the first time.Dans le cadre d’une enquête menée par Esra Erdoğan en Anatolie orientale, l’article présente les sceaux byzantins conservés dans quatre musées turcs : Malatya (l’ancienne Mélitène), Karaman (l’ancienne Laranda), Kahramanmaraş (l’ancienne Germanicée) et Nevşehir, en Cappadoce. L’intérêt de ces collections est d’offrir des perspectives renouvelées sur l’organisation administrative des provinces byzantines alors établies dans ces régions. Tous les sceaux ici présentés sont inédits.Cheynet Jean-Claude, Erdoğan Esra, Prigent Vivien. Sceaux des musées de la Turquie orientale : Karaman, Nevşehir, Malatya, Maraş. In: Revue des études byzantines, tome 74, 2016. pp. 287-326

Global thermodynamic approach of the molten core-concrete interaction (MCCI) and selected applications in the nuclear field

As part of a study on nuclear reactor safety, we modelled the thermodynamical properties of a complex mixture called "corium" obtained in the unlikely event of a severe accident in a nuclear power plant, if the reactor core melts through the vessel and slumps into the concrete reactor cavity. When the core and the concrete interact, the phenomenon is called "Molten Core-Concrete Interaction" (MCCI). The equilibrium state of the corium is calculated by the GEMINI2 program linked to the database TDBCR, which includes the thermochemical properties of the main constituents of the different materials present in a pressurized water reactor. The methodology of assembling a self-consistent database and some selected applications are presented. Such an approach is essential to increase the knowledge base of the material "corium" to feed other codes assigned to nuclear reactor safety

Mesoporosity in Photocatalytically Active Oxynitride Single Crystals

International audienc