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Decorating metal oxides with wide band-gap semiconductor nano-particles constitute an important approach for synthesizing nano-photocatalysts, where the photocatalytic activity is attributed to the band diagram related effective charge separation and external in-band quantum yield (EIQY). However, up to now, the correlation between the irradiation intensity and the functionalization of the in-band quantum yield has not yet been explained. In this work, by investigating the photocatalytic activity of ZnO and CuO/ZnO (CZO) nano-photocatalysts under various irradiative intensities, we show that the effective charge separation in the CuO/ZnO band alignment is sensitive to weak illumination, while ZnO exhibits a competitive photocatalytic activity with CZO under strong illumination. As a consequence, by modifying the irradiation intensity, the intrinsic ZnO can achieve a similar photocatalytic activity to that of metal oxide decorated ZnO. Besides, the optimal photocatalytic activity of CZO is found to be reachable by manipulating the pollutant concentration.

International audience; Reduced Au-Cu/CeO 2 catalysts (Cu/Au = 1, 3) are more efficient towards the preferential oxidation of CO (PROX) than their calcined counterparts. They exhibit lower activation energies and CO partial reaction orders (a CO), and even more interestingly, significantly higher O 2 partial reaction orders (b O2). For the sto-ichiometric composition in particular (Au 1 Cu 1 /CeO 2-R), the partial pressure of oxygen has a higher impact on the reaction rate than the partial pressure of CO (b O2 > a CO), which is unprecedented in low temperature catalysis involving gold and a reducible oxide support. DRIFTS studies further show (1) that Au 1 Cu 1 /CeO 2-R contains electron-deficient, alloyed Cu atoms (Au-Cu +) and (2) that the formation of CO 2 is enhanced by the preadsorption of O 2 rather than the preadsorption of CO. This suggests that CO oxidation proceeds via a Langmuir-Hinshelwood-type, bifunctional mechanism, involving CO adsorbed on Au 0 sites and oxygen adsorbed on electron-deficient, gold-alloyed copper sites. This alloy-mediated oxygen activation could be the key to the superior PROX activity of Au 1 Cu 1 /CeO 2-R.

International audience; Most of the pumps working under two phase flows conditions are used in petroleum industry applications, like electrical submersible pumps (ESP) for hydrocarbon fluids, in chemistry, nuclear industries and in agriculture for irrigation purposes as well. Two-phase flows always deteriorate overall pump performances compared with single flow conditions. Several papers have been published aiming to understand flow physics and to model all the main mechanisms that govern gas pocket formation and surging phenomena. These mechanisms depend on the pump type, the impeller geometry, the rotational speed, design and off-design liquid flow rate conditions, the volumetric gas fraction, the fluid properties and the inlet pressure. In the present paper, a review on two phase performances from various centrifugal pumps designs is presented, mainly based on experimental results. The main focus is devoted to detect the significant geometrical parameters that: (1) Modify the pump head degradation level under bubbly flow regime assumption; (2) Allow single stage centrifugal pumps keep working under two-phase flow conditions with high inlet void fraction values before pump shut down, whatever the pump performance degradations and liquid production rates should be. Because most of the published experimental studies are performed on dedicated laboratory centrifugal pump models, most of the present review is based on air-water mixtures as the working fluid with inlet pressures close to atmospheric conditions. The following review supposes that gas phase is considered as a non-condensable perfect gas, while the liquid phase is incompressible. Both phases are isolated from external conditions: neither mass nor heat transfer take place between the phases.

International audience; The present contribution aims to examine the erosion behavior of soda-lime-silica glass in connection with damage interaction and angle effects. Experimental observations are reported on glass plates subjected to sandblasting process using alumina abrasive particles for different sandblasting durations and impact angles. The damage and erosion mechanisms are computed through a numerical model of the sandblasted glass plate. The glass internal stiffness degradation due to impact process is accounted for by an anisotropic stress-based continuum damage mechanics model. The glass erosion is simulated by means of a vanishing element technique using the critical values of damage components as failure criterion. A parametric numerical study is carried out to bring insights into damage interaction and angle effects on the material loss.

International audience; This paper proposes an effective approach for modelling and assessing the risks associated with unmanned aerial vehicles (UAVs) integrated into national airspace system (NAS). Two critical hazards with UAV operations are considered and analyzed, which are ground impacts and midair collisions. Threats to fatalities that result from the two hazards are the focus in the proposed method. In order to realize ground impact assessment, a multifactor risk model is designed by calculating system reliability required to meet a target level of safety for different UAV categories. Both fixed-wing and rotary-wing UAVs are taken into account under a real scenario that is further partitioned into different zones to make the evaluation more precise. Official territory and population data of the operation scenario are incorporated, as well as UAV self-properties. Casualty area of impacting debris can be obtained as well as the probability of fatal injuries on the ground. Sheltering factors are not neglected and defined as four types based on the real scenario. When midair collision fatality risk is estimated, a model of aircraft collisions based on the density of civil flight in different regions over Chinese airspace is proposed. In the model, a relative collision area and flying speed between UAVs and manned aircraft are constructed to calculate expected frequency of fatalities for each province correspondingly. Truthful data with different numbers of UAVs is incorporated in the model with the expected number of fatalities after a collision is included. Experimental simulations are made to evaluate the ground impacts and midair collisions when UAVs operate in the NAS.

In this paper we present a 5G Internet Radio-Light (IoRL) architecture for supermarkets that can be readily deployed because it utilizes unlicensed visible light and millimeter wave part of the spectrum and which is used to provide shoppers with accurate location, interaction, access to Internet and Cloud based services such as high resolution video on a Tablet PC. The paper describes the supermarket use cases, the user and functional requirements and the IoRL architecture.

International audience; Time-of-use (TOU) pricing has been implemented by many electricity suppliers to alleviate the peak load of power grid, which provides a good opportunity for industrial consumers to reduce their energy bills. In industrial enterprises that involve batch processing machines, energy expenditure often accounts for large portion of the final product cost. Optimizing batch scheduling under TOU tariffs in these enterprises will be of great significance. This study investigates a single machine batch scheduling problem under TOU tariffs. The objective is to minimize the total electricity cost by optimally scheduling all jobs within a given planning horizon. Two mixed integer linear programming (MILP) models, which are respectively based on time-index formulation and time-interval formulation, are developed for the problem. The models are solved by CPLEX. Computational results on randomly generated instances demonstrate the effectiveness of the proposed approaches.