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Recent work showed that carbon nanotubes could be fabricated into bucky-paper structures as self-supporting membranes and their hydrophobic property used for water desalination by membrane distillation. Carbon nanotube bucky-papers possess very interesting properties such as natural hydrophobicity, high porosity and very high specific surface area, making of them promising candidates for separation applications. However, to inhibit crack formation associated with poor mechanical stability, improved durability structures that retain a high degree of hydrophobicity need to be developed. In this work we chemically modified high purity carbon nanotubes by (i) UV/ozone treatment to create hydroxyl groups and (ii) reacting those groups by substitution with alkoxysilane based groups. The resulting nanotubes presented a silicon content up to 2.5% and the bucky-papers produced had larger contact angle (140° compared to 125°) and liquid entry pressures. We report here on their fabrication and use as membranes in direct contact membrane distillation.

In this study, three types of sludge-derived biochars (BC1, BC2 and BC3) were prepared by 1) original sludge, 2) sludge after K2FeO4 conditioning, and 3) sludge after acidification + K2FeO4 conditioning. The results show that the biochar prepared from the conditioned sludge has additional functional groups, and its Pb2+ removal effect is greatly enhanced. The concentration of Pb2+ in the effluent can be reduced to

Supported gold and platinum particles on titanium oxide catalysts were evaluated in the oxidative depolymerization of lignins toward high added value aromatics under mild conditions (T: 150 °C, Pair: 20 bar, CNaOH: 10 g/L, 1 h). Kraft and ethanol Organosolv lignins were engaged in the study. Gold catalyst showed a strong tendency to further oxidize aromatics produced from lignin depolymerization to volatile compounds leading to very low yield in target molecules. On the contrary, platinum-based catalysts were allowed to observe enhanced yields that were attributed to its ability to preserve lignin’s substructure during the reaction. A kinetic model was constructed based on the results observed, which allowed us to identify the occurrence of condensation reactions during lignin oxidation and degradation of the produced aromatic compounds as the main limitations to reach high product yields. Insights on lignin oxidation and the catalyst’s role lead through this study would help to reach higher control over lignin valorization.

International audience; Modular structures are crystal structures built by subperiodic (zero-, mono-or diperiodic) substructures, called modules. The whole set of partial operations relating substructures in a modular structure build up a groupoid; modular structures composed of identical substructures are described by connected groupoids, or groupoids in the sense of Brandt. A general approach is presented to describe modular structures by Brandt's groupoids and how to obtain the corresponding space groups, in which only the partial operations that have an extension to the whole crystal space appear.

The analysis of the photoabsorption spectra of molecules shows that the band maximum is usually redshifted in comparison to the vertical excitation. We conducted a throughout analysis of this shift based on low-dimensional analytical and numerical model systems, showing that its origin is rooted in the frequency change between the ground and the excited states in multidimensional systems. Moreover, we deliver a benchmark of ab initio results for the shift based on a comparison of vertical excitations and band maxima calculated with the nuclear ensemble approach for the 28 organic molecules in the Mülheim molecular dataset. The mean value of the shift calculated over 60 transitions is 0.11 ± 0.08 eV. The mean value of the band width is 0.32 ± 0.14 eV. Graphical abstract. Electronic supplementary material The online version of this article (10.1007/s00894-020-04355-y) contains supplementary material, which is available to authorized users.

The increasing population creates excess pressure on the plantation and production of fruits and vegetables across the world. Consumption demand during the whole year has made production compulsory in the covered production system (greenhouse). Production, harvesting, processing, transporting, and distribution chains of fruit and vegetables have resulted in a huge amount of wastes as an alternative source to produce biofuels. In this study, optimization of two pretreatment processes (NaOH and HCl assisted thermal) was investigated to enhance methane production from fruit and vegetable harvesting wastes (FVHW) that originate from greenhouses. NaOH concentration (0&ndash, 6.5%), HCl concentration (0&ndash, 5%), reaction temperature (60&ndash, 100 &deg, C), solid content (1&ndash, 5%), time of reaction (1&ndash, 5 h), and mixing speed (0&ndash, 500 rpm) were chosen in a wide range of levels to optimize the process in a broad design boundary and to evaluate the positive and negative impacts of independent variables along with their ranges. Increasing NaOH and HCl concentrations resulted in higher COD solubilization but decreased the concentration of soluble sugars that can be converted directly into methane. Thus, the increasing concentrations of NaOH and HCl in the pretreatments have resulted in low methane production. The most important independent variables impacting COD and sugar solubilization were found to be chemical concentration (as NaOH and HCl), solid content and reaction temperature for the optimization of pretreatment processes. The high amount of methane productions in the range of 222&ndash, 365 mL CH4 gVS&minus, 1 was obtained by the simple thermal application without using chemical agents as NaOH or HCl. Maximum enhancement of methane production was 47&ndash, 68% compared to raw FVHW when 5% solid content, 1-hour reaction time and 60&ndash, C reaction temperature were applied in pretreatments.

International audience; Magnetic moment measurements of isomeric states in neutron-rich isotopes populated in photofission using γ-beam facility at the Extreme Light Infrastructure−Nuclear Physics (ELI-NP) laboratory aim at addressing many open questions related to the structure of the nuclei in A around 100 and 130 mass regions. The possibility of such measurements at ELI-NP is briefly discussed here using Geant4 Monte Carlo simulations. The present paper report the estimates of γ-beam profile at the target, fission fragment production rates and the possible target geometry.

Vine shoots are lignocellulosic agricultural residues. In addition to being an interesting source of polyphenols, they can be used as fillers in a poly(3-hydroxybutyrate-3-hydroxyvalerate) (PHBV) matrix to decrease the overall cost and to propose an alternative to non-biodegradable fossil-based materials. The objective of the present work was to investigate how the incorporation of vine shoots fillers and a preliminary polyphenol extraction step could impact the biodegradability of biocomposites. Biocomposites (20 wt %) were produced by microcompounding. The biodegradation of materials was assessed by respirometric tests in soil. The negative impact of polyphenols on the biodegradability of vine shoots was confirmed. This was supported by crystallinity measurements and scanning electron microscopy (SEM) observations, which showed no difference in structure nor morphology between virgin and exhausted vine shoots particles. The incorporation of vine shoots fillers in PHBV slightly accelerated the overall biodegradation kinetics. All the biocomposites produced were considered fully biodegradable according to the French and European standard NF EN 17033, allowing the conclusion that up-cycling vine shoots for the production of lignocellulosic fillers is a promising strategy to provide biodegradable materials in natural conditions. Moreover, in a biorefinery context, polyphenol extraction from vine shoots has the advantage of improving their biodegradability.

In Table 2 of this Full Paper, the units for the turnover frequencies (TOF) are given as 10-13 s-1. The correct units for the TOF are 10-3 s-1. The authors and editorial office apologize for the oversight.

This article describes the observation and determination of -module defects (twins, translation faults and module dislocations) in NiZr by high-resolution electron microscopy (HREM), and scanning transmission electron microscopy bright-field (STEM-BF) and high-angle annular dark-field (STEM-HAADF)., Some specific structures of intermetallic alloys, like approximants of quasicrystals, have their unit cells and most of their atoms located on a periodic fraction of the nodes of a unique -module [a set of the irrational projections of the nodes of a (N > 3-dimensional) lattice]. Those hidden internal symmetries generate possible new kinds of defects like coherent twins, translation defects and so-called module dislocations that have already been discussed elsewhere [Quiquandon et al. (2016 ▸). Acta Cryst. A72, 55–61; Sirindil et al. (2017 ▸). Acta Cryst. A73, 427–437]. Presented here are electron microscopy observations of the orthorhombic phase NiZr – and its low-temperature monoclinic variant – which reveal the existence of such defects based on the underlying -module generated by the five vertices of the regular pentagon. New high-resolution electron microscopy (HREM) and scanning transmission electron microscopy high-angle annular dark-field (STEM-HAADF) observations demonstrate the agreement between the geometrical description of the structure in five dimensions and the experimental observations of fivefold twins and translation defects.

Ted Janssen’s contributions to the field of aperiodic crystals are reviewed., This article reviews some of Ted Janssen’s (1936–2017) major contributions to the field of aperiodic crystals. Aperiodic crystals are long-range ordered structures without 3D lattice translations and encompass incommensurately modulated phases, incommensurate composites and quasicrystals. Together with Pim de Wolff and Aloysio Janner, Ted Janssen invented the very elegant theory of superspace crystallography that, by adding a supplementary dimension to the usual 3D space, allows for a deeper understanding of the atomic structure of aperiodic crystals. He also made important contributions to the understanding of the stability and dynamics of aperiodic crystals, exploring their fascinating physical properties. He constantly interacted and collaborated with experimentalists, always ready to share and explain his detailed understanding of aperiodic crystals.

International audience; Sugar-based surfactants are renewable alternatives to petroleum-based surfactants in many applications such as detergents and cosmetics. However, their molecular structure often gives rise to relatively stable crystals, which can lead to difficulties in dissolving them in water. This phenomenon is characterized by the Krafft temperature (T K), above which the surfactant solubility becomes high enough to induce self-association into micelles. Small changes in the molecular structure can result in large T K differences, which make rationalization and prediction of T K challenging. Few models were proposed in the literature, but none of them are applicable to sugar-based surfactants. In this article, we propose two decision tree models to estimate whether sugar-based surfactants exhibit potential dissolution issues at room temperature (i.e., T K above 25 °C or not). The first one, based on the descriptors of the whole molecule including quantum-chemical ones, was able to correctly classify 86% of the surfactants in the validation set. The second one, built from simple structural counts of the polar headgroup and the alkyl chain, could predict the right class for 78% of the surfactants in the validation set. These classification models account for experimentally known trends between the molecular structure and T K, such as the impact of the polar headgroup size, the alkyl chain length, and the presence of an amide linkage. To the end, our models were applied to a practical case to show how they can help in designing synthesis procedures of new surfactants.

International audience; Membrane fouling remains the major obstacle for development of membrane bioreactors (MBRs). This paper aimed at investigating the effects of carbamazepine (CBZ) present in a discontinuous way at high concentration (peak injection) on fouling propensity of activated sludge from a MBR that treats domestic wastewater. Batch experiments with peak injection of CBZ (100 mu g L-1 in sludge for 3 h) were performed for sludges sampled from a MBR operated under different organic loading conditions. HPLC-SEC analysis with a fluorescence detector was employed to study the effects of CBZ on protein-like compounds in supernatant. With addition of CBZ in sludge, a significant increase of sludge fouling propensity was observed when using sludge sampled from the MBR operated under low organic loading rate (0.1 kg COD/ kg EVESS/d), which could be attributed to the increase in the quantity of protein-like substances with a 100-1000 kDa molecular size in supernatant. Whereas reduced CBZ effect was found for sludge sampled from the MBR operated under higher organic loading rate (0.2 kg COD/kg MLSS/d). Whatever the sludge, the injection of CBZ induced no significant change of the floc size distribution and of the polysaccharide concentration in supernatant. Moreover, it did not affect the sludge microbial activity.

Since solvents of petroleum origin are now strictly regulated worldwide, there is a growing demand for using greener, bio-based and renewable solvents for extraction, purification and formulation of natural and food products. The ideal alternative solvents are non-volatile organic compounds (VOCs) that have high dissolving power and flash point, together with low toxicity and less environmental impact. They should be obtained from renewable resources at a reasonable price and be easy to recycle. Based on the principles of Green Chemistry and Green Engineering, vegetable oils could become an ideal alternative solvent to extract compounds for purification, enrichment, or even pollution remediation. This review presents an overview of vegetable oils as solvents enriched with various bioactive compounds from natural resources, as well as the relationship between dissolving power of non-polar and polar bioactive components with the function of fatty acids and/or lipid classes in vegetable oils, and other minor components. A focus on simulation of solvent-solute interactions and a discussion of polar paradox theory propose a mechanism explaining the phenomena of dissolving polar and non-polar bioactive components in vegetable oils as green solvents with variable polarity. Edinson Yara Varón thanks to fellowship funding (No. TECSPR14-2-0029) from the People Programme (Marie Curie Actions) of the Seventh Framework Programme of the European Union (FP7/2007-2013) under REA grant agreement No. 600388 (TECNIOspring programme), and from the Agency for Business Competitiveness of the Government of Catalonia, ACCIÓ. Ying Li would like to thank the National Natural Science Foundation of China (Grant 31701633) and the Fundamental Research Funds for the Central Universities (Grant 17817028), as well as special funds from “SanWu Talent 2014” and sixth “100-Talent” Programs.

International audience; Auguste Bravais by his fundamental work on lattice has pioneered modern crystallography. He was born in 1811 in Annonay (France) at a short distance from Lyon and Saint-Etienne. He was then educated at the College Stanislas in Paris and entered the École Polytechnique in Paris in 1829. In 1832, he joined the French Navy as an officer and took part at scientific explorations to the Algerian Coast and Northern Europe. In 1837 he defended a PhD in Astronomy at the Faculty of Sciences in Lyon where he became Professor in 1841 to teach mathematics in astronomy. Then, in 1845, he moved at Ecole Polytechnique in Paris to take the chair of Physics, which he held till 1856. He published his first studies dealing with crystal lattice in 1849 in a short paper [1] and later wrote a book where he developed his theory fully based on geometrical theorems [2]. He died prematurely in 1863 exhausted by the loss of his only son. Like many scientists of that time Auguste Bravais was universalist and has been successively astronomer, geologist, mathematician, physicist, mineralogist, and crystallographer as well as an explorer from Lapland to the top of Mont Blanc [3]. In this communication, the steering committee Lyon-Saint-Etienne will recall the contribution of Auguste Bravais to crystallography and will show some aspect of his life that may be less known in our community.

• The presence of nanostructures is demonstrated in a ternary melt of ethanol, 1-heptanol and rapeseed oil.

Despite the several advantages of microfiltration, applications of this separation technique in fruit juice industries have been challenged by its low economical productivity due to membrane fouling. Although several studies aimed to identify operating conditions (e.g. juice pretreatment, crossflow filtration mode, etc.) to achieve acceptable performances, only few studies focused on the fouling propensity of fruit juices and on the identification of their foulant compounds. The aim of this work was to evaluate the fouling behavior of two orange juices and focused on the identification of relevant size-classes of foulant particles. Lab-scale filtration tests were carried out in conjunction with juice size-fractionation with the aim of quantifying the resistance to filtration of the juices. Based on a resistance-in-series approach, size-cartographies of foulant particles that are juice and membrane-specific were built. These cartographies were provided for two mineral membranes M 1.2 and M 0.2 with different average pore diameters (1.2 and 0.2 μm). M 1.2 results showed that the fouling is mainly external for both juices and due to particles larger than 2 µm. In contrast, results concerning M 0.2 filtration tests showed that four different size-classes of fruit juices compounds are involved in different fouling mechanisms. Moreover, the hydraulic reversibility of the fouling mechanisms was evaluated through the impact of shear rate on the measured resistances. It was seen that the fouling was mainly reversible when M 1.2 was used for both juices filtration while it was not the case when juices were filtered with M 0.2 . This information would be interesting to choose the appropriate strategy in order to enhance the microfiltration of these juices at large scale. Moreover, the proposed size-cartography strategy would greatly satisfy the industrial demand for practical tool to identify the different size-classes of compounds governing the overall membrane fouling.

International audience; Zinc Oxide (ZnO) and graphene (G) have been extensively studied because of their unique physical properties. Here, Graphene-Zinc Oxide (G/ZnO) nanolaminates were fabricated, respectively, by chemical vapor deposition and low temperature atomic layer deposition technique. The number of obtained G/ZnO layers was tuned from 1 to 11 with a total thickness of 100 nm for all prepared nanolaminates. The structure, optical properties and interaction between G and ZnO were studied by X-ray methods, TEM, AFM, Raman and optical spectroscopy. The obtained results were interpreted and analysed taking into account strain and charge effects of graphene in G/ZnO nanostructures. We demonstrate that the bottom graphene used as a substrate stimulated the formation of ZnO crystalline structure. n-doping of graphene caused by charge transfer from ZnO to graphene has been detected by blue-shift of G-band of Raman spectra of the nanolaminates. ZnO photoluminescence intensity was found to be dependent on the number of graphene layers in G/ZnO nanolaminate. n-doping of graphene could be tailored by controlling the construction of the G/ZnO nanolaminates for variety of applications such as, for example, selective adsorption of the target molecules on graphene surface. Thus, G/ZnO nanolaminates may find applications in optical, bio-and chemical sensors.

An improvement of the sludge electrodewatering process is proposed: the anode flushing by filtrate recirculation. According to this technique, the mixture of filtrates obtained at cathode and anode sides, is used for continuous flushing of anode chamber of the filter press during electrodewatering. The anode flushing is aimed to eliminate essential problems of electrodewatering: ohmic heating, rise of electric energy consumption, electrodes corrosion, and filtrate contamination. This is attained by better control of the filtrate pH, the filter cake temperature and the dryness at anode side, where the physicochemical conditions are most aggressive. The efficiency of the proposed technique is evaluated at lab scale on drilling sludge electrodewatering with and without anode flushing. In experiments without anode flushing, increasing of electric current density caused strong increase of anode temperature, desiccation of the filter cake at anode side, rise of voltage and significant alkaline contamination of filtrate. The application of anode flushing allowed controlling the electric field strength and the temperature. Thus, the dewatering of the sludge has been extended at high electric field without damaging the filter equipment by drastic heating. Furthermore, it reduced the filtrate contamination by neutralization of the electrolysis products.

International audience; Due to water scarcity, development of innovative processes for wastewater reuse has become a priority. Hence, hybrid processes coupling membrane separation with advanced oxidation processes could play a decisive role in the production of safe water. However, membrane fouling is still one of the main limitations to process widespread application. Thus, the present study investigates the impact of e-beam irradiation on the fouling ability of a secondary effluent (SE) filtered on MF and subsequently on RD membranes. For this, two electron beam radiation doses (1 and 5 kGy) were investigated. Results demonstrate that whatever the radiation dose investigated, no change in terms of TOC in SE was observed (prior to filtration). However, a strong decrease in 1JV254 and fluorescence signal was observed for organic matter (OM) exhibiting a MW ranging from 135 to 10 kDa. Pre -oxidation was found to efficiently optimize ME filtration permeate flux whereas no improvement could be observed regarding RD separation. Moreover it was demonstrated that ME efficiently removed the high MW compounds and was barely efficient in low MW compounds removal. Energetic balance based on experimental results demonstrates that 1 kGy was a sufficient dose to operate the hybrid e-beam irradiation and ME process.

International audience; We present an introduction to the rapidly growing field of epitaxial graphene on silicon carbide, tracing its development from the original proof-of-concept experiments a decade ago to its present, highly evolved state. The potential of epitaxial graphene as a new electronic material is now being recognized. Whether the ultimate promise of graphene-based electronics will ever be realized remains an open question. Silicon electronics is based on single-crystal substrates that allow reliable patterning on the nanoscale, which is an absolute requirement for any new electronic material. That is why epitaxial graphene is based on single-crystal silicon carbide. We also present recent results on nanopatterned graphene produced by etching the silicon carbide before annealing so that the graphene structures are produced in their final shapes. This avoids post annealing patterning, which is known to greatly affect transport properties on the nanoscale. Creating such structured graphene is an elegant method for avoiding pervasive patterning problems.

The key limitation to the application of reverse osmosis (RO) desalination on inland brackish waters is concentrate disposal. Due to precipitation of sparingly soluble salts (CaCO3, CaSO4, BaSO4, SrSO4), RO membrane recovery cannot be increased further; therefore, other strategies must be investigated. Antiscalants are often added to RO feed water to help prevent precipitation and increase RO recovery, but in concentrate treatment, antiscalants may prevent precipitation of problematic constituents. A threestage process to treat brackish water RO concentrate was investigated; the stages include oxidation of antiscalants with ozone and hydrogen peroxide, precipitation at elevated pH, and solid/liquid separation. A model water concentrate was used to perform laboratory scale experiments for each treatment stage. Experimental results showed that the advanced oxidation process (AOP) of ozonation and hydrogen peroxide on phosphonate antiscalants allowed increased calcium precipitation as well as loss of the solubilizing effects of antiscalants as compared to precipitation without prior ozonation of the antiscalants. The AOP also removed the effect of antiscalant on precipitate particle size distribution and particle morphology. In some cases, the AOP also improved microfiltration performance for the solid/liquid separation stage. The concentrate treatment could increase overall recovery from 80% to 90% for non-ozonated, antiscalant-dosed concentrate and from 80% to 94% for ozonated, antiscalant-dosed concentrate. © 2010 Published by Elsevier B.V.

To determine the technical and economic feasibility of cross-flow microfiltration on an industrial scale, the expected decline of permeation flux must be predicted taking into account the variability of juice's fouling potential. However, the main difficulty is finding representative parameters. Two semi-empirical models – gel polarisation and mechanistic – were used to fit experimental permeation flows using initial juice turbidity as surrogate for the volumetric concentration of particles in the feed juice. The experimental data of different banana, pineapple, and blackberry juices fitted well in both models. Although the mechanistic model more accurately estimated the permeation flux density, for practical application, the simpler polarisation model was preferred. Because this method uses a factor (i.e. turbidity) that reflects juice's fouling potential, it allows the optimisation of processing parameters and the prediction of permeation flux range in real industrial conditions.

Issu de : WasteEng 2008, Patras, GREECE, 3-5 June 2008; International audience; The number of waste disposal sites decreases and redundant poles, piling and lumber, which constitute a large volume of material, may not be accepted at the limited number of sites in the future. CCA contaminated wood contains around 1-5% of metal in form of arsenic pentoxide, hexavalent and trivalent chromium compounds and copper sulfate, which act as fungicides and insecticides throughout the life of the wood. While CCA treatment is gradually becoming a banned practice, approximately 4 million tonnes of CCA treated wood is generated in the EU per year, which is set to continue for many decades as the in-service wood is generated in end of its life. Recycling wood waste is important for the effective utilization of natural resources. The charcoal product resulting from CCA treated wood contains Cu, Cr and As. The metals appear as both agglomerates and diffused in the solid matrix. Moreover, during pyrolysis an agglomeration process takes place, which induces not only the growth of existing mineral agglomerates but also the formation of new agglomerates. The objective of the present work is the valorisation of CCA metals and charcoal from treated wood waste. The research aims at understanding and promoting experimentally, at different pyrolysis heating rates, the generation of charcoal with high specific surface area from pyrolysed treated wood waste.

cited By 8; International audience; In order to obtain new compounds with antitumoural action the N-(meta-acylaminobenzoyl)-α-acylaminobenzoyl)-α-aminoacids 4-9 were prepared. These compounds were subsequently converted into the corresponding Δ2-oxazolin-5-ones 10-15, which in turn were submitted to a ring opening reaction with di-(β-chloroethyl)amine to afford the peptide supported N-mustards 16-21, which showed low toxicity and cytostatic activity similar to that of sarcolisine against the Ehrlich ascite and Walker 253 carcinosarcoma. © 2007 by MDPI.

International audience; An electron-transfer chain reaction between 2-nitropropane anion and α-bromoketones derived from nitrobenzene and nitrothiophene was demonstrated by mechanistic study and a specific convenient synthetic protocol. Thus, 2-bromo-1-(5-nitrothiophen-2-yl)ethanone or 2-bromo-1-(4-nitrophenyl)ethanone were reacted with several cyclic nitronate anions to form α,β-unsaturated ketones via a SRN1 mechanism. This new method can be used to synthesize a wide variety of chalcone analogues.

The Bayer process is used for refining bauxite into smelting grade alumina (Al2O3), which is the precursor of aluminium. The process was developed and patented by Karl Josef Bayer 110 years ago and has become the cornerstone of the aluminium production industry worldwide. This study focuses on the characterization of the main liquor of the Bayer process, or Bayer liquor (BL) in terms of viscosity, composition and organic carbon distribution as a function of the molecular weight. It then shows that the purification of BL by nanofiltration helps to enhance the production of alumina. The organic carbon is well retained, which makes it possible to send a permeate back into the process, thus, increasing the whiteness and quality of the precipitated alumina crystals. Moreover, most of the other impurities are concentrated in the nanofiltration retentate. In view of the good results obtained on the Bayer liquor, this study is extended to the other effluent or solution of the Bayer process: nanofiltration can be used to retain more than 78% of most of the impurities present in these effluents.

International audience; Deep-frying, which consists of immersing a wet material in a large volume of hot oil, presents a process easily adaptable to dry rather than cook materials. A suitable material for drying is sewage sludge, which may be dried using recycled cooking oils (RCO) as frying oil. One advantage is that this prepares both materials for convenient disposal by incineration. This study examines fry-drying of municipal sewage sludge using recycled cooking oil. The transport processes occurring during fry-drying were monitored through sample weight, temperature, and image analysis. Due to the thicker and wetter samples than the common fried foods, high residual moisture is observed in the sludge when the boiling front has reached the geometric center of the sample, suggesting that the operation is heat transfer controlled only during the first half of the process followed by the addition of other mechanisms that allow complete drying of the sample. A series of mechanisms comprising four stages (i.e., initial heating accompanied by a surface boiling onset, film vapor regime, transitional nucleate boiling, and bound water removal) is proposed. In order to study the effect of the operating conditions on the fry-drying kinetics, different oil temperatures (from 120 to 180 degrees C), diameter (D = 15 to 25 mm), and initial moisture content of the sample (4.8 and 5.6 kg water(.)kg(-1) total dry solids) were investigated.

International audience; Cell biologists have long aimed at quantitatively modeling cell function. Recently, the outstanding progress of high-throughput measurement methods and data processing tools has made this a realistic goal. The aim of this paper is twofold: First, to suggest that, while much progress has been done in modeling cell states and transitions, current accounts of environmental cues driving these transitions remain insufficient. There is a need to provide an integrated view of the biochemical, topographical and mechanical information processed by cells to take decisions. It might be rewarding in the near future to try to connect cell environmental cues to physiologically relevant outcomes rather than modeling relationships between these cues and internal signaling networks. The second aim of this paper is to review exogenous signals that are sensed by living cells and significantly influence fate decisions. Indeed, in addition to the composition of the surrounding medium, cells are highly sensitive to the properties of neighboring surfaces, including the spatial organization of anchored molecules and substrate mechanical and topographical properties. These properties should thus be included in models of cell behavior. It is also suggested that attempts at cell modeling could strongly benefit from two research lines: (i) trying to decipher the way cells encode the information they retrieve from environment analysis, and (ii) developing more standardized means of assessing the quality of proposed models, as was done in other research domains such as protein structure prediction.

International audience; SARS-CoV-2 remains infectious for several hours on surfaces. It can be inactivated by UV-C irradiation but optimal conditions for rapid inactivation, especially on non-plastic surfaces remains unclear. A SARS-CoV-2 inoculum was irradiated with a UV-C LED (265 nm) or a UV-C mercury lamp (254 nm). Infectivity titers (TCID50/mL) and inactivation rates were then quantified on plastic, steel, tissue, paper and cardboard surfaces. We demonstrated that efficient SARS-CoV-2 inactivation (> 99.999% on plastic and steel, ≥ 99.8% on tissue, paper and cardboard) can be achieved by both a UV-C mercury lamp and a UV-C LED after 30 s of irradiations at 3 cm, corresponding to UV-C doses of 92.85 and 44.7 mJ/cm2, respectively. Inactivation on a plastic surface was more efficient with the mercury UV-C lamp (p < 0.005). The mercury UV-C lamp could be more relevant than the LED in high-risk settings, such as medical care or research laboratories.

International audience; This tutorial review paper consolidates the existing applications of the power watershed (PW) optimization framework in the context of image processing. In literature, it is known that PW framework when applied to some well-known graph-based image segmentation and filtering algorithms such as random walker, isoperimetric partitioning, ratio-cut clustering, multi-cut and shortest path filters yield faster yet consistent solutions. In this paper, the intuition behind the working of PW framework i.e. exploitation of contrast invariance on image data is explained. The intuitions are illustrated with toy images and experiments on simulated astronomical images. This article is primarily aimed at researchers working on image segmentation and filtering problems in application areas such as astronomy where images typically havea huge number of pixels. Classic graph-based cost minimization methods provide good results on images with small number of pixels but do not scale well for images with large number of pixels. The ideas from the article can be adapted to a large class of graph-based cost minimization methods to obtain scalable segmentation and filtering algorithms.

International audience; To advance an understanding of key electrochemical and photocatalytic processes that depend on the electronic structure of aqueous solutions, X-ray photoemission spectroscopy has become an invaluable tool, especially when practiced with liquid microjet setups. Determining vertical ionization energies referenced to the vacuum level, and binding energies referenced to the Fermi level, including the much-coveted reorganization energy of the oxidized species of a redox couple, requires that energy levels be properly defined. The present paper addresses specifically how the vacuum level "just outside the surface" can be known through the energy position of the rising edge of the secondary electrons, and how the Fermi level reference is uniquely determined via the introduction of a redox couple. Taking the case of the ferricyanide/ferrocyanide and ferric/ferrous couples, the paper also tackles issues related to the electrokinetic effects inherent to the production of a liquid jet in vacuum, which has become the standard water sample environment for photoemission experiments.

International audience; In catalytic industrial processes, coke deposition remains a major drawback for solid catalysts use as it causes catalyst deactivation. Extensive study of this phenomenon over the last decades has provided a better understanding of coke behavior in a great number of processes. Among them, catalytic pyrolysis of plastics, which has been identified as a promising process for waste revalorization, is given particular attention in this paper. Combined economic and environmental concerns rose the necessity to restore catalytic activity by recovering deactivated catalysts. Consequently, various regeneration processes have been investigated over the years and development of an efficientand sustainable process remains an industrial challenge. Coke removal can be achieved via several chemical processes, such as oxidation, gasification, and hydrogenation. This review focuses on oxidative treatments for catalyst regeneration, covering the current progress of oxidation treatments and presenting advantages and drawbacks for each method. Molecular oxidation with oxygen and ozone, as well as advanced oxidation processes with the formation of OH radicals, are detailed to provide a deep understanding of the mechanisms and kinetics involved (direct and indirect oxidation, reaction rates and selectivity, diffusion, and mass transfer). Finally, this paper summarizes all relevantanalytical techniques that can be used to characterize deactivated and regenerated solid catalysts: XRD, N2 adsorption-desorption, SEM, NH3-TPD, elemental analysis, IR. Analytical techniques are classified according to the type of information they provide, such as structural characteristics, elemental composition, or chemical properties. In function of the investigated property, this overall tool is useful and easy-to-use to determine the adequate analysis.

In the present paper, a half-wave plate (HWP) based on a birefringent metamaterial is numerically designed to operate in the visible range. The proposed structure consists of an array of double-pattern perpendicular rectangular aperture (RAA) engraved into opaque silver film deposited on a glass substrate. One of the apertures is glass filled. The operating principle of this plate is based on the excitation and the propagation of one guided mode inside each aperture but with different effective index. At the output side, a phase difference is obtained whose value mainly depends on the metal thickness. We have investigated the most simplest configurations using a homemade code based on the finite difference time domain method to design a half-plate with optimized efficiency resulting in transmission coefficient of more than $60\%$ together with a birefringence of $2.1$ at an operation wavelength of 737 nm. This kind of anisotropic metasurface promises a wide range of applications in integrated photonics., pages, 8 figures, Original paper

International audience; This paper reports the synergetic effects of UV and visible light irradiation on the photocatalytic activity of well-defined nanostructures composed of TiO2 films and Au nanoparticles (NPs). New insights into electronic as well as chemical processes that drive water decomposition were obtained by varying the position of the NPs on top and at different depths inside the semiconductor film. This work highlights the synergetic effect of UV and visible light on the photocatalytic activity of all the Au-containing structures: hydrogen produced under UV + Vis light shows 100% enhancement compared to the net production obtained under either UV or visible light alone. The systems where Au NPs are embedded in TiO2 outperform the one where NPs are positioned on the surface, indicating that the water-splitting reaction occurs primarily on the TiO2 surface rather than on the metal. Photocurrent and photocatalytic activity measurements under UV (353–403 nm), visible (400–1100 nm), and UV + Vis (300–1100 nm) light revealed the synergetic contribution of UV and Vis light. Indeed, the plasmonic Au NPs create an intense oscillating electric field at the Au NPs/semiconductor interface (visible light contribution); this mechanism coupled with the Schottky barrier formation generates hot electrons resulting in a better photoexcited charge separation. In addition, contrary to what is generally assumed, charge injection by the plasmon from the metal into the semiconductor plays a marginal role in the hydrogen evolution reaction. Furthermore, this paper highlights the positive impact of the semiconductor crystallinity surrounding the metal particles to avoid the charge carrier recombination and the importance of a surface free of oxygen vacancies, whose presence can inhibit the water decomposition.

International audience; Van Dijk's Comment draws attention to the fact that the local pressure tensor, P(r), in an equilibrium system that is inhomogeneous is not uniquely defined at the nano-scale, as seen in Eq. (4) of our paper 1 , where the configurational term on the right involves an integral along a contour Cij connecting the centres of two molecules, i and j. The choice of this contour is arbitrary, resulting in the non-uniqueness of P. Physically, the non-uniqueness arises because the intermolecular forces are between two molecules located at ri and rj, i.e. they are non-local, whereas we wish to determine the pressure at a local point r, and there is no unique way to assign part of the non-local pair force to the local point r. To pursue the statistical mechanical approach to P one must first make an operational definition of the contour. All of this is well known in the statistical mechanical community. It is implicit in Kirkwood and Buff's 1949 paper 2 , and is discussed at some length in an Appendix of the seminal paper of Irving and Kirkwood (IK) 3. Irving and Kirkwood 3 , writing 70 years ago, stated the situation clearly: "all definitions must have this in common-that the stress 4 definition between a pair of molecules be concentrated near the line of centers. When averaging over a domain large compared with the range of the intermolecular forces, these differences are washed out, and the ambiguity remaining in the macroscopic stress tensor is of negligible order." Further discussion of these points were given later

The numerous combinations of cations and anions turn out possible to produce ionic liquids with fine-tuned properties once the correlation with the molecular structure is known. In this sense, computer simulations are useful tools to explain and even to predict properties of ionic liquids. However, quantum mechanical methods are usually restricted to either small clusters or short timescales, so that the use of parametrized force fields is needed for studying the bulk liquids. A method is proposed in this work to enable a comparison between quantum mechanical and both polarizable and non-polarizable force fields by means of the calculation of free energy surfaces for the translational motion of the anion around the cation in gas phase. This method was tested for imidazolium-based cations with 3 different anions, [BF4]-, [N(CN)2]-, and [NTf2]-. It was found better agreement with the DFT calculations when polarizability is introduced in the forcefield. In addition, the ion pair free energy surfaces reproduced the main structural patterns observed in the first coordination shell in molecular dynamics simulations of the bulk liquid, proving to be useful probes for the liquid phase structure that can be computed with higher level methods and the comparison with forcefields can indicate further improvements in their parametrization., author submitted version of the paper published in J. of Chemical Physics on 02 January 2020. 40 pages with 15 figures in main paper plus 19 pages with 20 figures as Supporting Information attached by the end of the file

International audience; Nowadays, the use of nanofluids as alternative to commonly-used industrial heat transfer fluids is a topic of increasing interest. Analysing the improved efficiency of heat transfer processes according to advanced nanomaterials and obtaining stable nanofluids is one of the most interesting challenges. This paper presents a study of nanofluids based on boron nitride nanotubes and using an aqueous solution of Triton X-100 (which acts as a surfactant) as the base fluid. UV-vis spectroscopy, particle size measurements (size between 150 and 170 nm) and potential (at about 25 mV) showed that stable nanofluids were obtained. Surface tension measurements were also performed. The surface tension of water was weakly affected by the presence of any amount of nanoparticles and was mainly governed by the presence of surfactant. The rheological properties of the fluids were also analysed, as were their isobaric specific heat and thermal conductivity values. A Newtonian behaviour was observed for the base fluid and the nanofluids, with no significant increase in viscosity. The isobaric specific heat increased by 8% and thermal conductivity by 10% compared with the base fluid. Thus, the results obtained are interesting because while thermal properties improved with nanoparticle content, rheological behaviour did not change. Consequently, the nanofluids studied in the current paper do not raise the pressure drop and pumping power significantly and may therefore be a good option for thermal system applications.

International audience; In this paper, we demonstrate a new method to obtain a low gap between the access waveguide and the racetrack cavity of a micro-resonator based on porous silica material and using standard photolithographic process. The photolithographic process is first carried out on porous silicon layers to obtain porous silicon ridge waveguides that constitutes the racetrack micro-resonator. Then the full oxidation of the micro-resonator is performed. Because of the volume expansion of silicon that occurs during its full oxidation, the gap is reduced. Lower gaps and then lower coupling distances can be obtained using a low cost photolithographic process compared to e-beam technology. This original method proposed in this paper allows to improve the miniaturization of such porous silica micro-resonators which is of great interest for integrated optical biosensor application.

International audience; Porous polymeric materials with tunable porosity can be engineered from oligoester-derivatized semi-interpenetrating polymer networks (semi-IPNs) or IPNs, respectively composed of either uncrosslinked or crosslinked aliphatic oligoesters entangled in a stiff subnetwork. In this paper, miscellaneous polyester/poly(methyl methacrylate)-based semi-IPN and IPN systems are first prepared as precursors with varying structural parameters, especially the nature [i.e., poly(D,L-lactide), poly(ε-caprolactone)] and the molar mass (i.e., from 560 to 3700 g mol−1) of the oligoester precursor. (Nano)porous networks with defined porosity are then generated through two complementary routes. This original paper discusses the scope and limitations of both approaches and investigates the correlation between the structure and morphology of the generated networks and the porosity of the resulting porous materials. We demonstrate that the choice of the precursors with defined compatibility is of paramount significance in the length scale of phase separation associated with nanostructured networks as well as in the porosity scale of (nano)porous materials derived therefrom. Indeed, we find that the quantitative extraction of uncrosslinked oligoesters from semi-IPNs allows for the elaboration of nanoporous networks with pore diameters lower than 150 nm, provided that a high miscibility between both partners in semi-IPN precursors is attained, i.e. when using the lower molar mass oligoester. Alternately, the total hydrolysis of the polyester subnetwork associated with IPNs offers more versatility, since nanoporous networks can be obtained with a pore size range of 20–150 nm, regardless of the oligoester nature and molar mass in IPN precursors.

The extraction of inhomogeneous 3-dimensional densities around tagged solutes from molecular simulations is known to have a very high computational cost because this is traditionally performed by collecting histograms, with each discrete voxel in three-dimensional space needing to be visited significantly. This paper presents an extension of a previous methodology for the extraction of 3D solvent number densities with a reduced variance principle [Borgis et al., Mol. Phys. 111, 3486-3492 (2013)] to other 3D densities such as charge and polarization densities. The approach is also generalized to cover molecular solvents with structures described using rigid geometrical constraints, which include in particular popular water models such as SPC/E and TIPnP class of models. The noise reduction is illustrated for the microscopic hydration structure of a small molecule, in various simulation conditions, and for a protein. The method has large applicability to simulations of solvation in many fields, for example around biomolecules, nanoparticles, or within porous materials., Main paper 13 pages 8 figures. Supporting information 2 pages 4 figures. Published in the Journal of Chemical Physics

International audience; In this review paper, we have assembled the main characteristics of partial oxidation reactions (oxidative dehydrogenation and selective oxidation to olefins or oxygenates, as aldehydes and carboxylic acids and nitriles), as well as total oxidation, particularly for depollution, environmental issues and wastewater treatments. Both gas-solid and liquid-solid media have been considered with recent and representative examples within these fields. We have also discussed about their potential and prospective industrial applications. Particular attention has been brought to new raw materials stemming from biomass, as well as to liquid-solid catalysts cases. This review paper also summarizes the progresses made in the use of unconventional activation methods for performing oxidation reactions, highlighting the synergy of these technologies with heterogeneous catalysis. Focus has been centered on both usual catalysts activation methods and less usual ones, such as the use of ultrasounds, microwaves, grinding (mechanochemistry) and photo-activated processes, as well as their combined use.

International audience; Interest in graphite fillers has grown since the separation of graphene from graphite by micromechanical cleavage. The object of the paper is to understand the influence of graphene nanoplatelets (GNPs) with different sizes on the crystallization behavior of a polyolefin matrix such as polypropylene (PP), after elaboration by melt mixing and compression molding. Composites with volume fractions of graphene nanoplatelets ranging from 0.3 to 2 vol% were prepared. The particle dispersion states in the composites were characterized at different scales using Scanning and Transmission Electron Microscopies (SEM and TEM). Polypropylene crystallization and orientation were investigated using optical microscopy, Differential Scanning Calorimetry (DSC) and X-ray diffraction. This paper discusses the strong acceleration of crystallization kinetics due to the presence of GNPs. The micrometric flake-shaped GNPs act as nucleating agent and induce an epitaxial growth of alpha (α) crystalline phase of PP. The nucleating effect is related to the surface of the particles available for heterogeneous nucleation. Radial spherulitic growths are observed from the smallest micrometric particles. The coarsest GNPs, easily oriented by flow, favor PP transcrystallinity, in such a way that (010) plane of PP is parallel to (001) plane of graphene nanoplatelets.

International audience; The paper describes a joint refinement model of the spin-resolved one-electron reduced density matrix using simultaneously magnetic structure factors and magnetic directional Compton profiles. The model is guided by two strategies: (i) variation of basis functions and (ii) variation of the spin population matrix. The implementation for a finite system is based on an expansion of the natural orbitals on basis sets. To show the potential benefits brought by the joint refinement model, the paper also presents the refinement results using magnetic structure factors only. The joint refinement model provides very satisfactory results reproducing the pseudo-data. In particular, magnetic Compton profiles have a strong effect not only on the off-diagonal elements of the spin-resolved one-electron reduced density matrix but also on its diagonal elements.

With a view to finding which of the available equations of state is the most suitable for the representation of the thermodynamics of mixtures containing nitrogen, oxygen and argon, this paper mainly intends to address the comparison of the performance of the - already optimized - GERG-2008, Bender and Peng-Robinson (PR) Equations of State (EoS) in the calculation of Vapour-Liquid Equilibrium (VLE) and volumetric properties of N2-O2-Ar mixtures. The comparison between experimental measurements collected in the literature and model calculations has led to conclude about the overall superiority of GERG-2008. It is also shown that the Peng-Robinson EoS leads to comparable results in VLE calculations and that the use of Bender EoS should be avoided as it leads, despite its complex multiparameter formulation, to very inaccurate results in the calculation of VLE properties of the binary Ar-O2 and of volumetric properties. For completeness, the paper also shows the poor accuracy of the PR EoS in calculating VLE properties when zero-kij are selected. Moreover, the paper evaluates the impact of deviations on densities, calculated with the different equations of state, on the computation of transport properties (thermal conductivity, viscosity), in turns determined by means of correlations which are typically applied. Liquid thermal conductivity is highly affected by errors on liquid density calculations while the liquid viscosity is independent of density. Differently, errors on vapour thermal conductivity and dynamic viscosity are lower than those observed on vapour density.

International audience; Separator electrode assemblies (SEAs) were designed by associating a microbial anode with an air-cathode on each side of three different kinds of separator: plastic grid, J-cloth and baking paper. The SEA was designed to allow the air-cathode be removed and replaced without disturbing the bioanode. Power densities up to 6.4 W m−2 were produced by the Grid-SEAs (on average 5.9 ± 0.5 W m−2) while JCloth-SEAs and Paper-SEAs produced 4.8 ± 0.3 and 1.8 ± 0.1 W m−2, respectively. Power densities decreased with time mainly because of fast deterioration of the cathode kinetics. They always increased again when the air-cathodes were replaced by new ones; the Grid-SEAs were thus boosted above 4 W m−2 after 7 weeks of operation. The theoretical analysis of SEA functioning suggested that the high performance of the Grid-SEAs was due to the combination of several virtuous phenomena: the efficient pH balance thanks to free diffusion through the large-mesh grid, the likely mitigation of oxygen crossover thanks to the 3-dimensional structure of the bioanode and the possibility of overcoming cathode fouling by replacing it during MFC operation. Finally, the microbial community of all bioanodes showed stringent selection of Proteiniphilum acetatigenes in proportion with the performance.

International audience; In their seminal paper of 1923, Debye and Hückel provided the first appropriate description of the effect of ionic strength on the thermodynamic properties of dilute electrolyte solutions. This landmark work paved the way for what was later called the primitive model of electrolytes. At this level, an ionic solution is modeled as a collection of charged hard spheres in a dielectric continuum that manifests itself only through its dielectric constant. Numerical simulations have been reported in the literature for salts in a continuous solvent. In the present work, results obtained using various analytical theories are compared with Monte-Carlo (MC) simulation data (expected to be 'exact') taken from the literature, in the case of binary electrolytes in a continuous solvent mimicking water. The theories include the Debye-Hückel theory, the mean-spherical approximation (MSA), and the Pitzer approach. The MC data are about mean salt activity and osmotic coefficients, and also individual ion activity coefficients. Moreover, some remarks are made about the assumptions underlying the Debye-Hückel framework, and new formulas are derived for individual ion activity coefficients by following the method of Pitzer.

International audience; In a recent study, we showed by solid-state NMR that LiVPO4F, which is a promising material as positive electrode for Li-ion batteries, often exhibits some defects that may affect its electrochemical behavior. In this paper, we use DFT calculations based on the projector augmented-wave (PAW) method in order to model possible defects in this (paramagnetic) material and to compute the Fermi contact shifts expected for Li nuclei located in their proximity. The advantage of the PAW approach versus FP-LAPW we have been previously using is that it allows considering large supercells suitable to model a diluted defect. In the first part of this paper, we aim to validate the Fermi contact shifts calculation using the PAW approach within the VASP code. Then we apply this strategy for modeling possible defects in LiVPO4F. By analogy with the already existing homeotypic LiVOPO4 phase, we first replace one fluoride ion, along the VO2F4 chains, by an oxygen one and consider, in a second step, an association with a lithium vacancy. As a result, the agreement between the calculated NMR spectra and the experimental one is satisfying. In both cases, the local electronic structure and the spin transfer mechanisms from V3+ or V4+ ions to the Li nuclei are analyzed.

International audience; In a recent paper (J. Chem. Theory. Comput., 2017, 13, 180-190) we proposed the Truncated Conjugate Gradient (TCG) approach to compute the polarization energy and forces in polarizable molecular simulations. The method consists in truncating the Conjugate Gradient algorithm at a fixed predetermined order leading to a fixed computational cost and can thus be considered " non-iterative ". This gives the possibility to derive analytical forces avoiding the usual energy conservation (i.e. drifts) issues occurring with iterative approaches. key point concerns the evaluation of the analytical gradients, which is more complex than with an usual solver. In this paper, after reviewing the present state of the art of polarization solvers, we detail a viable strategy for the efficient implementation of the TCG gradients calculation. The complete cost of the approach is then mesured as it is tested using a multi-timestep scheme and compared to timings using usual iterative approaches. We show that the TCG method is more efficient than traditional techniques, making it a method of choice for future long molecular dynamics simulations using polarizable force fields where energy conservation matters. We detail the various steps required for the implementation of the complete method by software developers.

International audience; The aim of this paper is to describe concisely the recent theoretical and numerical developments concerning absorbing boundary conditions and perfectly matched layers for solving classical and relativistic quantum waves problems. The equations considered in this paper are the Schrödinger, Klein-Gordon and Dirac equations.