pinecone/core-2020-05-10-deduplication huggingface dataset:
The Effect of Production Parameters on the Performance of Carbon Anodes for Aluminium Production

Carbon anodes are essential when producing aluminium. Oxygen from dissolved aluminium oxide reacts electrochemically on the carbon anode forming CO2. The carbon anode is consumed during the process. The production of aluminium happens according to the electrochemical reaction:
2Al2O3 (diss) + 3C (s) = 4Al (l) + 3CO2 (g)
Carbon anodes are produced from calcined petroleum coke and a pitch binder. Anisotropic sponge coke was traditionally used as anode grade coke; however, the increased production of aluminium in the world has led to an increase in the demand for anode grade coke. Isotropic coke that was previously graded as fuel grade coke is being tested as anode grade coke in blends by some smelters around the world. In this work a series of pilot anodes have been made where the effect of blending isotropic coke into anisotropic coke was investigated. The pilot anodes were investigated both through characterisation techniques and electrochemical performance. Isotropic coke is higher in impurities (especially metals like vanadium and nickel, and sulfur) than many anisotropic sponge cokes and the increased impurity level can impose problems in the pot rooms. Also, the coefficient of thermal expansion between the two cokes is very different and this will cause increased cracking of anodes containing a certain level of isotropic coke. Cracking was observed in pilot anodes containing 35.0 wt% and 49.0 wt% isotropic coke. However, electrochemical testing showed that the introduction of isotropic coke to the pilot anodes proved positive in reducing the anodic reaction overpotential and also reducing the voltage oscillations caused by gas bubbles. Reducing the reaction overpotential can give a reduction in the energy consumption of the overall process, and reduction in voltage oscillations during bubble build-up and release will give more stable pots. It was also found that the wettability between the anode and the electrolyte was improved when isotropic coke was present. It is reasonable to assume a correlation between the reduction in voltage oscillations and improved wettability between anode and electrolyte.
The effect of the production parameters mixing temperature between pitch and coke, and baking temperature was also investigated in pilot anodes. A pilot anode line was prepared where the mixing and baking temperatures were varied: a high and a low mixing temperature and a medium and a low baking temperature. The electrochemical effect of varying these anode production parameters was small. However, the mixing temperature proved very important in order to produce homogeneous and dense anodes where the pitch had penetrated the coke well
CO2 reduction to syngas and carbon nanofibres by plasma-assisted in situ decomposition of water

Simultaneous activation of CO2 and H2O was carried out in a non thermal plasma dielectric barrier discharge reactor operated under ambient conditions. The plasma reactor packed with partially reduced NiO/Al2O3 catalyst showed better CO2 conversion than both the unreduced NiO/Al2O3 and with plasma (no catalyst), whereas, highest syngas selectivity was observed with unreduced NiO/Al2O3. An interesting observation is the formation of carbon nanofibres (CNFs) along with syngas with a reduced NiO catalyst integrated to the plasma, whereas, pure NiO only led to the formation of methane. The reduction of CO2 by in situ formation of hydrogen from water splitting may produce CH4 and plasma-assisted chemical vapour decomposition of CH4 may lead to the formation of CNF
Simulation of MPI applications with time-independent traces

International audienceAnalyzing and understanding the performance behavior of parallel applications on parallel computing platforms is a long-standing concern in the High Performance Computing community. When the targeted platforms are not available , simulation is a reasonable approach to obtain objective performance indicators and explore various hypothetical scenarios. In the context of applications implemented with the Message Passing Interface, two simulation methods have been proposed, on-line simulation and off-line simulation, both with their own drawbacks and advantages. In this work we present an off-line simulation framework, i.e., one that simulates the execution of an application based on event traces obtained from an actual execution. The main novelty of this work, when compared to previously proposed off-line simulators, is that traces that drive the simulation can be acquired on large, distributed, heterogeneous , and non-dedicated platforms. As a result the scalability of trace acquisition is increased, which is achieved by enforcing that traces contain no time-related information. Moreover, our framework is based on an state-of-the-art scalable, fast, and validated simulation kernel. We introduce the notion of performing off-line simulation from time-independent traces, propose and evaluate several trace acquisition strategies, describe our simulation framework, and assess its quality in terms of trace acquisition scalability, simulation accuracy, and simulation time
Non-D-finite excursions in the quarter plane

International audienceWe prove that the sequence $(e^{\mathfrak{S}}_n)_{n\geq 0}$ of excursions in the quarter plane corresponding to a nonsingular step set~$\mathfrak{S} \subseteq \{0,\pm 1 \}^2$ with infinite group does not satisfy any nontrivial linear recurrence with polynomial coefficients. Accordingly, in those cases, the trivariate generating function of the numbers of walks with given length and prescribed ending point is not D-finite. Moreover, we display the asymptotics of $e^{\mathfrak{S}}_n$
Dust distribution in protoplanetary disks - Vertical settling and radial migration

Accepted for publication in Astronomy & Astrophysics. 11 pages, 6 figures.International audienceWe present the results of a three dimensional, locally isothermal, non-self-gravitating SPH code which models protoplanetary disks with two fluids: gas and dust. We ran simulations of a 1 Msun star surrounded by a 0.01 Msun disk comprising 99% gas and 1% dust in mass and extending from 0.5 to ~300 AU. The grain size ranges from 0.001 mm to 10 m for the low resolution (~25 000 SPH particles) simulations and from 0.1 mm to 10 cm for the high resolution (~160 000 SPH particles) simulations. Dust grains are slowed down by the sub-Keplerian gas and lose angular momentum, forcing them to migrate towards the central star and settle to the midplane. The gas drag efficiency varies according to the grain size, with the larger bodies being weakly influenced and following marginally perturbed Keplerian orbits, while smaller grains are strongly coupled to the gas. For intermediate sized grains, the drag force decouples the dust and gas, allowing the dust to preferentially migrate radially and efficiently settle to the midplane. The resulting dust distributions for each grain size will indicate, when grain growth is added, the regions when planets are likely to form
Comparative Study of Immune Regulatory Properties of Stem Cells Derived from Different Tissues.

International audience: Allogeneic stem cell (SC)-based therapy is a promising tool for the treatment of a range of human degenerative and inflammatory diseases. Many reports highlighted the immune modulatory properties of some SC types, such as mesenchymal stromal cells (MSCs), but a comparative study with SCs of different origin, to assess whether immune regulation is a general SC property, is still lacking. To this aim, we applied highly standardized methods employed for MSC characterization to compare the immunological properties of bone marrow-MSCs, olfactory ectomesenchymal SCs, leptomeningeal SCs, and three different c-Kit-positive SC types, that is, amniotic fluid SCs, cardiac SCs, and lung SCs. We found that all the analyzed human SCs share a common pattern of immunological features, in terms of expression of activation markers ICAM-1, VCAM-1, HLA-ABC, and HLA-DR, modulatory activity toward purified T, B, and NK cells, lower immunogenicity of inflammatory-primed SCs as compared to resting SCs, and indoleamine-2,3-dioxygenase-activation as molecular inhibitory pathways, with some SC type-related peculiarities. Moreover, the SC types analyzed exert an anti-apoptotic effect toward not-activated immune effector cells (IECs). In addition, we found that the inhibitory behavior is not a constitutive property of SCs, but is acquired as a consequence of IEC activation, as previously described for MSCs. Thus, immune regulation is a general property of SCs and the characterization of this phenomenon may be useful for a proper therapeutic use of SCs
New developments in coastal environment research: results from the national coastal environment program

consultable à l'adresse suivante : http://archimer.ifremer.fr/doc/2007/publication-2621.pdfInternational audienceThe National Coastal Environment Program (PNEC) developed fundamental research on the coastal zones of France, in Europe and overseas. PNEC was funded by a consortium of seven French institutions (IFREMER, CNRS, IRD, Total, CNES, BRGM, CEMAGREF) represented in the inter-institute committee to decide the program orientations and budget breakdown. PNEC activities were coordinated with LITEAU programme supported by the French Ministry of Ecology and Sustainable Development, to make scientific results available to administrators and policy makers as methods and tools for coastal zone management
Perspectives from the French workshop on the development and validation of biomarkers and bioassays for the monitoring of aquatic environments

International audienceDuring the past three decades, there has been an increasing interest in the field of ecotoxicology for development of effect-based monitoring tools (EBMTs) including in vitro tests, biomarkers and whole organism bioassays. This interest is due to the practical application of EBMTs in the surveillance of the quality of water and aquatic ecosystems (ICES, 2008). Within this framework, these ecotoxicological tools seem to offer numerous potential advantages, as they allow one to take into account the cumulative impact of the whole contaminants present in the field, and the bio-available and active fractions of toxicants as well as their degradation bioaccumulation, biotransformation (Lam and Gray, 2003; Hecker and Hollert, 2009). Hence, they are often seen as complementary tools to conventional environmental monitoring approaches, mostly based on the measurement of a predefined list of chemical substances in various aquatic compartments (water, sediments and biota) and the analyses of indices of biological integrity (OSPAR 2004). Due to these research activities, several core EBMTs (SGIMC, 2011) are now well characterised and may be directly used to assess the quality of the aquatic environment under a European consensus (Table 1; Sanchez and Porcher, 2009; Lyons et al., 2010). However, if EBMTs are widely used in research studies and provide, at geographically and temporally limited scales, data on ecotoxicological status of water bodies, few applications of EBMTs are currently implemented in regulatory environmental monitoring programs
First-report on Mesozoic eclogite-facies metamorphism preceding Barrovian overprint from the western Rhodope (Chalkidiki, northern Greece)

International audienceThe Chalkidiki block in Northern Greece represents the southwesternmost piece of theultrahigh-pressure Rhodope and has played an important role in the evolution of the NorthAegean. The eastern part of the Chalkidiki block is a basement complex (Vertiskos Unit) thatis made largely of Palaeozoic granitoids and clastic sediments metamorphosed during theMesozoic. This basement is traditionally considered as part of the Rhodopean hanging-wall,an assignment mainly supported by the absence of high-pressure mineral indicators and thepresence of a regional medium-pressure/medium-temperature amphibolite-facies Barrovianmetamorphic imprint. Toward the west, the basement is juxtaposed with meta-sedimentary(Circum-Rhodope belt) and arc units (Chortiatis Magmatic Suite) that carry evidence of aMesozoic high-pressure/low-temperature event. In this study, garnet-staurolite-mica schistsfrom the eastern part of the basement were examined by means of micro-textures, mineralchemistry and isochemical phase-diagram sections in the system NCKFMASHMn(Ti)[Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-MnO-(TiO2)]. The schists represent formerMesozoic sedimentary sequences deposited on the Palaeozoic basement. We document thepresence of a relict eclogite-facies mineral assemblage (garnet + chloritoid + phengite +rutile) in an amphibolite-facies matrix composed of garnet + staurolite + phengite ± kyanite.Model results suggest the existence of a high-pressure/medium-temperature metamorphicevent (1.9GPa / 520°C) that preceded regional re-equilibration at medium-pressure/mediumtemperatureconditions (1.2GPa / 620°C). Clearly, the eastern part of the Chalkidiki block(basement complex) retains memory of an as yet unidentified Mesozoic eclogiticmetamorphic event that was largely erased by the later Barrovian overprint. In the light of ourfindings, the basement complex of the Chalkidiki block shares a common tectonometamorphicevolution with both the high-pressure units to the west, and the high-gradeRhodopean gneisses further to the northeast. Our results are consequential for the geodynamic reconstruction of the Rhodope since they require participation of the Chalkidikiblock to the well-established Mesozoic subduction system
Statistical characteristics of flow as indicators of channeling in heterogeneous porous and fractured media

International audienceWe introduce two new channeling indicators Dic and Dcc based on the Lagrangian distribution of flow rates. On the basis of the participation ratio, these indicators characterize the extremes of both the flow-tube width distribution and the flow rate variation along flow lines. The participation ratio is an indicator biased toward the larger values of a distribution and is equal to the normalized ratio of the square of the first-order moment to the second-order moment. Compared with other existing indicators, they advantageously provide additional information on the flow channel geometry, are consistently applicable to both porous and fractured media, and are generally less variable for media generated using the same parameters than other indicators. Based on their computation for a broad range of porous and fracture permeability fields, we show that they consistently characterize two different geometric properties of channels. Dic gives a characteristic scale of low-flow zones in porous media and a characteristic distance between effectively flowing structures in fractured cases. Dcc gives a characteristic scale of the extension of high-flow zones in porous media and a characteristic channel length in fractured media. Dic is mostly determined by channel density and permeability variability. Dcc is, however, more affected by the nature of the correlation structure like the presence of permeability channels or fractures in porous media and the length distribution in fracture networks
A species-dependent bio-optical model of case I waters for global ocean color processing

International audienceThe PHYSAT method, which enables identification of four different phytoplankton groups from their impact on the normalized water-leaving radiance (nLw) spectra, is applied to coincident in situ measurements of both chlorophyll a concentration (Chl a) and nLw. Observations show that measurements acquired in waters dominated by haptophytes, diatoms and Synechococcus-like cyanobacteria have optical properties that deviate significantly from the mean OC4V4 bio-optical model, which is currently used as the standard for global ocean color processing. A specific OC4v4-like relationship, i.e., Chl a as a 4th-order polynomial of the "maximum band ratio", was fitted for each dominant phytoplankton group identified by PHYSAT. The resulting OC4-SD bio-optical model thus starts from a classification of the dominant phytoplankton group, followed by a species-dependent estimate of Chl a. It has been applied to global daily SEAWIFS data of the year 2001. Monthly mean maps of Chl a derived from OC4-SD or OC4v4 show large regional differences that can reach 50% at high latitudes.The new algorithm leads to lower concentrations in regions where the standard model retrievals are known to be too high, such as the Mediterranean Sea. Conversely, higher concentrations are retrieved in regions dominated by diatom blooms, such as the northern North Atlantic in summer, where previous studies have demonstrated a low bias in standard SEAWIFS Chl a
Optical flow for incompressible turbulence motion estimation

International audienceWe propose in this paper a new formulation of optical flow dedicated to 2D incompressible turbulent flows. It consists in minimizing an objective function constituted by an observation term and a regularization one. The observation term is based on the transport equation of the passive scalar field. For non-fully resolved scalar images, we propose to use the mixed model in large eddy simulation to determine the interaction between large scales and unresolved ones. The regularization term is based on the continuity equation of 2D incompressible flows. Compared to prototypical method, this regularizer preserves more vortex structures by eliminating constraints over the vorticity field. The evaluation of the proposed formulation is done over synthetic and experimental images, and the improvements in term of estimation are discussed
Haliea salexigens gen. nov., sp. nov., a member of the Gammaproteobacteria from the Mediterranean Sea

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2008/publication-4193.pdfInternational audienceA novel aerobic, Gram-negative bacterium, designated 3X/A02/235T, was isolated from the surface of coastal waters in the north-western Mediterranean Sea. Cells were motile, straight rods, 1.6 microm long and 0.5 microm wide, and formed cream colonies on marine agar medium. The G+C content of the genomic DNA was 61 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed the strain in the class Gammaproteobacteria and within the family Alteromonadaceae. On the basis of 16S rRNA gene sequence comparisons and physiological and biochemical characteristics, this isolate represents a novel species of a novel genus, for which the name Haliea salexigens gen. nov., sp. nov. is proposed. The type strain of Haliea salexigens is 3X/A02/235T (=DSM 19537T =CIP 109602T =MOLA 286T)
Predictive control of disturbed systems with input delay: experimental validation on a DC motor

International audienceThis paper deals with the speed control of a DC motor with known input delay and unknown disturbances. A recent predictive technique is used in order to design two controllers that will be able to satisfactorily reject disturbances in spite of the time delay. A comparison between the Artstein reduction method and this new one is performed throughout the article. The control laws are validated first by simulation and then by a practical implementation. The paper presents the very first application of this new predictive method
Stick-slip waves between elastic and rigid half-spaces

International audienceThe construction of an analytic solution of the problem of stick-slip waves crossing the interface between an elastic half-space and a tigid one under unilateral contact and Coulomb friction is considered. The method of solution is based on the analytic continuation method of Radok's complex potentials within the framework of steady elastodynamic problems. The governing equations combined with the boundary conditions are reduced to a Riemann-Hilbert problem with discontinuous coefficient, and closed-form expressions of the solution are derived. It is found that the existence of solutions depends on the additional velocity, which is related to the longitudinal elongation. If this velocity is ignored, there is no solution, if not, it is possible to construct weakly singular solutions satisfying all stick-slip conditions except over a narrow zone where the waves exhibit a crack-like behaviour
An asymptotic strain gradient Reissner-Mindlin plate model

In this paper we derive a strain gradient plate model from the three-dimensional equations of strain gradient linearized elasticity. The deduction is based on the asymptotic analysis with respect of a small real parameter being the thickness of the elastic body we consider. The body is constituted by a second gradient isotropic linearly elastic material. The obtained model is recognized as a strain gradient Reissner-Mindlin plate model. We also provide a mathematical justification of the obtained plate model by means of a variational weak convergence result
Homogenized Interface Model Describing Inhomogeneities Located on a Surface

International audienceWe study the influence of heterogeneities located near a planar surface on the elastic response of a three-dimensional elastic medium. These heterogeneities can be either reinforcements, like steel reinforce- ments in concrete, or defects, like micro-cracks periodically distributed. We prove that their influence is of the second order from an energetic viewpoint. Then, we propose an "up to second order effective model" in which the influence of the heterogeneities is given by a surface energy contribution involving both the jump of displacement across the surface and the tangential strain components on the surface. The effective coefficients entering in the definition of the surface energy are obtained by solving "elementary" elastic problems formulated on an infinite representative cell containing the defects. We analyze this model, in particular the properties of the effective surface coefficients, and establish its coherence with limit models previously described in the literature for stiff or soft interfaces. This approach is finally applied to several kinds of heterogeneities
Improvement of FAO-56 Model to Estimate Transpiration Fluxes of Drought Tolerant Crops under Soil Water Deficit: Application for Olive Groves

Agro-hydrological models are considered an economic and simple tool for quantifying crop water requirements. In the last two decades, agro-hydrological physically based models have been developed to simulate mass and energy exchange processes in the soil-plant-atmosphere system. Although very reliable, because of the high number of required variables, simplified models have been proposed to quantify crop water consumes. The main aim of this paper is to propose an amendment of the Food and Agricultural Organization (FAO) of the United Nations FAO-56 spreadsheet program to introduce a more realistic shape of the stress function, valid for mature olive orchards (Olea europaea L.). The modified model is successively validated by means of the comparison between measured and simulated soil water contents and actual transpiration fluxes. These outputs are finally compared with those obtained with the original version of the model. Experiments also allowed assessing the ability of simulated crop water stress coefficients to explain the actual water stress conditions evaluated on the basis of measured relative transpirations and midday stem water potentials. The results show that the modified model significantly improves the estimation of actual crop transpiration fluxes and soil water contents under soil water deficit conditions, according to the RMSEs associated with the revised model, resulting in significantly higher than the corresponding values obtained with the original version