The Experts below are selected from a list of 56139 Experts worldwide ranked by ideXlab platform
Yuegang Zhang - One of the best experts on this subject based on the ideXlab platform.
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liquid phase electrochemical scanning electron microscopy for in Situ Investigation of lithium dendrite growth and dissolution
Advanced Materials, 2017Co-Authors: Genlan Rong, Xinyi Zhang, Wen Zhao, Fangmin Ye, Yan Xu, Jiafan Chen, Wanfei Li, Wenhui Duan, Yuegang ZhangAbstract:: An in Situ electrochemical scanning electronic microscopy method is developed to systematically study the lithium plating/stripping processes in liquid electrolytes. The results demonstrate that the lithium dendrite growth speed and mechanism is greatly affected by the additives in the ether-based electrolyte.
Camille Loupiac - One of the best experts on this subject based on the ideXlab platform.
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ex Situ and in Situ Investigation of protein exopolysaccharide complex in porphyridium cruentum biomass resuspension
Algal Research-Biomass Biofuels and Bioproducts, 2019Co-Authors: Thierry Tran, Céline Lafarge, Rémi Pradelles, Nathalie Cayot, Pascale Winckler, Camille LoupiacAbstract:Abstract During the extraction processes of B-phycoerythrin from P. cruentum, the possibility of the occurrence of extraction-inhibiting B-phycoerythrin/exopolysaccharide (EPS) complexes was highlighted. The use of confocal laser scanning microscopy allowed the observation of the cells including their sheath and their chloroplast, the bound EPS matrix, and extracellular vesicles involving phycobiliproteins and EPS in P. cruentum biomass resuspensions. The observations were performed using autofluorescence and fluorescence marking. pH variations showed more impact than ionic strength increase induced by NaCl addition on the B-phycoerythrin content and the organization of vesicles. Namely, agglomeration of the vesicles could be observed at pH 8.5 without NaCl addition. With addition of 1 M NaCl, this phenomenon was prevented but the vesicles were not visibly dissociated for any pH value. These results point towards a precipitate rather than a coacervate, which are expected to have narrow stability conditions regarding pH and ionic strength. In an attempt to dissolve or break the vesicles and the extracellular matrix, successive macerations in water and use of high pressure homogenizer process in one-step or two-step treatments were applied to the resuspensions. The successive macerations could free the cells and the vesicles from the extracellular matrix, whereas the homogenizer treatment disrupted the extracellular matrix, the vesicle and a part of the cells. In our case, only the successive macerations showed a positive extraction since the high pressure treatment caused unwanted denaturation. It is concluded that more experiments in model conditions could help understand the nature of the interactions between phycobiliproteins and EPS leading to the formation of the vesicles. Porphyridium cruentum, confocal fluorescence microscopy, complexation, B-phycoerythrin, exopolysaccharide.
Fengyuan Zhang - One of the best experts on this subject based on the ideXlab platform.
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in Situ Investigation of bubble dynamics and two phase flow in proton exchange membrane electrolyzer cells
International Journal of Hydrogen Energy, 2018Co-Authors: Zhenye Kang, Gaoqiang Yang, Derrick A Talley, Bo Han, Fengyuan ZhangAbstract:Abstract Gas bubble dynamics and two-phase flow have a significant impact on the performance and efficiency of proton exchange membrane electrolyzer cells (PEMECs). It has been strongly desired to develop an effective experimental method for in-Situ observing the high-speed/micro-scale oxygen bubble dynamics and two-phase flow in an operating PEMEC. In this study, the micro oxygen bubble dynamic behavior and two-phase flow are in-Situ visualized through a high-speed camera coupled with a specific designed transparent PEMEC, which uses a novel thin liquid/gas diffusion layer (LGDL) with straight-through pores. The effects of different operating conditions on oxygen bubble dynamics, including nucleation, growth, and detachment, and two-phase flow have been comprehensively investigated. The results show that temperature and current density have great effects on bubble growth rate and reaction sites while the influence of flow rate is very limited. The number, growth rate, nucleation site, and slug flow regime of oxygen gas bubbles increase as temperature and/or current density increases, which indicates that an increase in temperature and/or current density can enhance the oxygen production efficiency. Further, a mathematical model for the bubble growth is developed to evaluate the effects of temperature and current density on the bubble dynamics. A mathematical model has been established and shows a good correlation with the experimental results. The studies on two-phase flow and high-speed micro bubble dynamics in the microchannel will help to discover the true electrochemical reaction at micro-scale in an operating PEMEC.
Alexander Michaelis - One of the best experts on this subject based on the ideXlab platform.
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anodic dissolution behaviour and surface texture development of cobalt under electrochemical machining conditions
Electrochimica Acta, 2013Co-Authors: M Schneider, N Schubert, Soren Hohn, Alexander MichaelisAbstract:Abstract The anodic dissolution of hcp-cobalt in sodium nitrate solution under near-ECM conditions was investigated in Situ by using a specially designed flow channel cell. The in Situ Investigation was focused on current densities of 5 A/cm 2 and 10 A/cm 2 . Cobalt dissolves actively as cobalt (II) ion with a current efficiency close to 100%. In contrast to copper, the current–voltage relation does not show an active–passive transition. The dissolution strongly depends on the crystallographic orientation of the grains. The lowest dissolution rate was observed on plains vicinal to the basal plane {0 0 0 1}. No gas evolution was observed. The surface roughness is determined by the micro roughness on the individual grains.
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in Situ Investigation of the surface topography during anodic dissolution of copper under near ecm conditions
Materials and Corrosion-werkstoffe Und Korrosion, 2012Co-Authors: M Schneider, S Schroth, N Schubert, Alexander MichaelisAbstract:Electrochemical machining is characterized by deliberate high speed anodic dissolution. The distance between anode and cathode are only a few hundred microns. Additionally, the electrolyte flow rate is in the range of approximately meter/second. A special electrochemical cell design was developed to investigate the surface topography during the anodic dissolution simultaneously and in-Situ under near-ECM conditions. The anode was directly placed under the cathode with a gap of 350 µm. We carried out pulse experiments at 15 A/cm2 and 25 A/cm2 with an electrolyte flow rate of 4m/s. First-time it was possible to observe the surface changing of the anode directly during current pulses by using a video camera. Different stages e.g. roughening, film formation or gas evolution could be distinguished.
Gilles Armand - One of the best experts on this subject based on the ideXlab platform.
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In Situ Investigation of the THM Behavior of the Callovo-Oxfordian Claystone
Rock Mechanics and Rock Engineering, 2020Co-Authors: Nathalie Conil, Manon Vitel, Carlos Plua, Minh Ngoc Vu, Darius Seyedi, Gilles ArmandAbstract:The thermo-hydro-mechanical behavior of the host rock is essential while designing an underground radioactive waste disposal repository, and in particular, while considering the long-term safety of the facility. In 2000, the French National Radioactive Waste Management Agency (Andra) started constructing an underground research laboratory located in the Meuse Haute Marne to carry out a research program aiming to demonstrate the feasibility of constructing and operating a radioactive waste disposal facility in the Callovo-Oxfordian claystone, and to optimize its implementation. To study the thermo-hydro-mechanical effects of the early thermal phase on the clay host rock of a deep repository, Andra has performed various in Situ heating tests; one of them is called the TED experiment. The aim of the TED experiment was to measure the evolution of the temperature and pore pressure fields around several heaters and to back-analyze the thermo-hydro-mechanical properties of the Callovo-Oxfordian claystone. Thermal conductivity and heat capacity values were determined based on the back-analysis of the in Situ measurements and compared to those measured on samples. The in Situ experimental data and numerical model confirm the anisotropic behavior of the claystone. The TED experiment results demonstrate the ability of current models to predict the evolution of temperature and pore pressure in the far field of disposal cells.
