78 research outputs found
Formation des complexes ternaires alcalino-terreux/uranium/carbonate. Données thermodynamiques et influence sur la spéciation et la solubilité de l'uranium dans différents contextes géochimiques
No full textLa formation des complexes carbonate d’uranyle(VI) est primordiale pour la compréhension de la chimie et du transport de l’uranium. Les complexes ternaires triscarbonato-uranyle d’alcalino-terreux, Mᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻ (M = Mg²⁺ et Ca²⁺) mis en évidence depuis la fin des années 1990, sont susceptibles de contrôler la chimie de l’uranium – et donc sa solubilité ou ses propriétés d’adsorption – dans des environnements variés, depuis l’eau de mer jusqu’aux milieux géologiques de stockage. Les données thermodynamiques de ces complexes restent sujettes à controverses. En plus des alcalino-terreux, l’influences des cations alcalins n’est pas claires entre l’influence de la force ionique de la solution ou l’influence des ions alcalins sur la structure des complexes. Ce travail de thèse se propose de clarifier les domaines d'existence des complexes Mᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻ en fonction de la force ionique en étudiant l'influence additionnelle des cations alcalins. Le choix de la technique analytique s’est porté sur la spectrofluorimétrie laser à résolution temporelle (SLRT). La quantification des mesures de luminescence des complexes Mᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻ est faite pour les analyses laboratoires. La présence des complexes étudiées dans les échantillons synthétiques peut être vérifiée par les bandes caractéristiques et les temps de décroissance. Dans ce travail, les données thermodynamiques en réponse à la température et à la force ionique pour les complexes (Mg/Ca)ᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻ en milieux NaCl et NaClO₄ sont très utiles pour estimer les effets de la température et de la salinité sur la spéciation de l'U(VI), en particulier dans les dépôts de déchets nucléaires, et pour combler les lacunes dans la base de données thermodynamiques pour ces complexes étudiées.The formation of carbonato complexes of uranyl(IV) is of great importance for the understanding of the chemistry and transport of uranium. The ternary alkaline-earth triscarbonato-uranyl complexes, Mᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻ (M = Mg²⁺and Ca²⁺), evidence in the late 1990’s, can control the uranium chemistry – and its solubility and adsorption properties – in various environments, including deep geological disposal, surface waters, and seawater. Thermodynamic data for these ternary complexes are still a matter of debate. In addition of alkaline-earths, the influence of alkaline cations is not clearly settled between the ionic strength effect and the influence on the structure of complexes. The aim of this thesis is to clarify the existence domains of Mᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻ complexes as a function of ionic strength by studying the additional influence of alkali ions. Time- resolved laser spectrofluorimetry (TRLFS), a highly sensitive technique to probe the characteristic features of uranium species, was chosen as the analytical technique in this work. The quantification of Mᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻complexes from luminescence measurements was done for laboratory analysis. The presence of the studied complexes in the synthetic samples can be verified by their characteristic bands and decay times. In this work, the thermodynamic data with respect to temperature and ionic strength for the (Mg/Ca)ᵢ[UO₂(CO₃)₃]⁽⁴⁻²ⁱ⁾⁻ complexes in NaCl and NaClO₄ media are very useful for estimating the effects of temperature and salinity on the speciation of U(VI), especially in nuclear waste repositories, and for filling in the gaps in the thermodynamic database for these complexes
Formation of alkaline earth(II) triscarbonatouranyl(VI) complexes: thermodynamic study and ionic strength influence by time-resolved laser-induced fluorescence spectroscopy
No full textInternational audienc
Memantine induces manic episode in a 73-year-old patient with vascular neurocognitive disorder: a case report
No full textJinfeng Duan,1,2 Chengming Lao,3,4 Jingkai Chen,1,2 Fen Pan,1,2 Chenlin Zhang,3 Weijuan Xu,1,2 Weihua Zhou,1,2 Jianbo Hu,1,2 Desheng Shang,1 Manli Huang,1,2 Yi Xu1,2 1Department of Psychiatry, First Affiliated Hospital, College of Medicine, Zhejiang University, The Key Laboratory of Mental Disorder’s Management of Zhejiang Province, Hangzhou, People’s Republic of China; 2Brain Research Institute of Zhejiang University, Hangzhou, People’s Republic of China; 3College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 4Yiwu Mental Health Center, Yiwu, People’s Republic of China Abstract: Memantine, an N-methyl-D-aspartate receptor antagonist, is a well-established treatment option for moderate-to-severe cognitive impairment related to Alzheimer disease. Recently, growing evidence has indicated memantine might also be effective in treatment of affective disorders. The common drug-induced adverse events of memantine include confusion, dizziness, drowsiness, headache, insomnia, and agitation. Herein, we presented a case of a 73-year-old female patient with vascular neurocognitive disorder, who developed a manic episode after taking memantine. Keywords: memantine, depression, dementia, manic episod
BladeSynth: Damage Detection and Assessment in Aircraft Engines with Synthetic Data
No full textDeep learning has been widely implemented in industrial inspection, such as damage detection from images. However, training deep networks requires massive data, which is hard to collect and laborious to annotate, especially in the aviation scenario of aircraft engines. To alleviate the demand for annotated data, we create BladeSynth - a large synthetic image dataset for detecting damage from aircraft engines, and empirically evaluate the transferability of state-of-the-art Scaled-YOLOV4 from synthetic to real world by pre-training on synthetic data and fine-tuning on real data. Our experiments show that pre-training on synthetic data improves the performance in damage detection in aircraft engine images.Electrical Engineerin
Determination of formation constants and specific ion interaction coefficients for CaUO(CO) complexes in NaCl solution by time-resolved laser-induced luminescence spectroscopy
No full textInternational audienceThe formation constants of CaUO(CO) and CaUO(CO)(aq) were determined in NaCl medium at ionic strengths between 0.1 and 1 mol kg using time-resolved laser-induced luminescence spectroscopy (TRLS). Spectroluminescence titration of UO(CO) complex by Ca were conducted at atmospheric CO(g) and varying pH values in order to eliminate the eventual precipitation of both schoepite (UO : 2HO) and calcite (CaCO) in aqueous solutions. To identify the stoichiometry of calcium, the slope analyses corrected by the Ringböm coefficient for UO(CO) relative to pH and CO(g)—instead of typical expression relative to UO and CO—was applied in this work. Satisfactory linear fits assessed the conditional stepwise formation constants in the range of ionic strength employed in this work, the values of which are in good agreement with literature data at comparable ionic strengths. Extrapolations to infinite dilution were realized in the framework of the specific ion interaction theory (SIT), also providing the evaluation of the specific ion interaction coefficients. The cumulative stability constants at infinite dilution was determined to be log β°(CaUO(CO)) = 27.20 ± 0.04 and log β°(CaUO(CO)(aq)) = 30.49 ± 0.05, which are in good agreement with extrapolation proposed elsewhere in literature using a different extrapolation framework. The specific ion interaction coefficients were found to be ε(CaUO(CO),Na) = (0.29 ± 0.11) and ε(CaUO(CO)(aq),NaCl) = (0.66 ± 0.12) kg mol. Integration of alkali metals into the ternary species may explain these positive and relatively large interaction coefficients. Implications on the speciation of uranium in clay groundwaters, representative of radioactive waste repositories, and in seawater are discussed
Effect of temperature on the complexation of triscarbonatouranyl(VI) with calcium and magnesium in NaCl aqueous solution
No full textInternational audienceThe complex formation of triscarbonatouranyl(VI) UO(CO) with the alkaline earth metal ions Mg and Ca in 0.10 mol kg NaCl was studied at variable temperatures: 5–30 °C for Mg and 10–50 °C for Ca. Under appropriate conditions, the ternary complexes (MUO(CO) with n = 1 for Mg, n = {1; 2} for Ca) were identified by time-resolved laser-induced luminescence spectrometry. Their pure spectral components at 50 °C for CaUO(CO) and 30 °C for MgUO(CO) were recovered by multivariate curve resolution alternating least-squares analysis. Approximation models were tested to fit the experimental data—the equilibrium constants of complexation measured at different temperatures —and deduce the thermodynamic functions, i.e., enthalpy, entropy, and heat capacity. The weak influence of temperature on complexation constants induces large uncertainties in terms of thermodynamic functions. Assuming the enthalpy is constant with temperature using the Van’t Hoff equation, the first stepwise complexation of UO(CO) by Ca is estimated to be slightly endothermic, with = (4.9 ± 5.9)kJ mol, while the second stepwise complexation of CaUO(CO) by Ca with is slightly exothermic, = -(6.2 ± 13.3) kJ mol. In contrast to Ca, the complexation of UO(CO) by Mg is slightly exothermic, with = -(11.7 ± 10.3) kJ mol. These values are not significantly different from zero inasmuch as the uncertainties are important due to a weak dependence of log K° values. The entropic character of the complexation is verified as = (36.5 ± 6.0) kJ mol for the first stepwise complexation of UO(CO) by Ca, = (13.8 ± 13.3) kJ mol for the second stepwise complexation of CaUO(CO) by Ca, and = (14.2 ± 10.3)= kJ mol for the complexation of UO(CO) by Mg. The energetics of complexation and sensitivity analysis of the model estimates with temperature are discussed. The uranium speciation in the case of the safety of nuclear waste management, using the present thermodynamic functions, provides support to the assessment of underground nuclear waste repositories
The determination of the thermodynamic constants of MgUO(CO) complex in NaClO and NaCl media by time-resolved luminescence spectroscopy, and applications in different geochemical contexts
No full textInternational audienc
Études des systèmes luminescents alcalino-terreux–uranium(VI)–carbonate et curium(III)–citrate par SLRT et techniques avancées de traitement de données
No full textNational audienceL’uranium, présent à l’état de traces dans la croûte terrestre et les eaux naturelles, suscite des préoccupations de santé et d’environnement. Comprendre sa spéciation, surtout en complexes de carbonates d’uranyle(VI), est crucial pour évaluer son comportement dans divers milieux. Les complexes tricarbonatouranyles d’alcalino-terreux influencent la solubilité et les propriétés d’adsorption de l’uranium, mais leurs données thermodynamiques sont encore débattues. La spectrofluorimétrie laser à résolution temporelle (SLRT), technique non intrusive, permet d’étudier ces complexes en préservant les conditions des solutions. La recherche se concentre sur les complexes CanUO2(CO3)3(4-2n)– dans des solutions de NaCl et NaClO4, révélant des écarts dans les constantes de formation par rapport aux valeurs conventionnelles, signe d’interactions ioniques complexes. La SLRT a aussi été utilisée pour caractériser les complexes curium(III)–citrate, montrant des changements spectroscopiques dus aux interactions chimiques. Ces résultats affinent les données thermodynamiques nécessaires pour comprendre la spéciation de l’uranium et d’autres actinides dans des environnements complexes
Spectroluminescence measurements of the stability constants of CaUO(CO) complexes in NaClO medium and the investigation of interaction effects
No full textInternational audienc
China's transportation sector carbon dioxide emissions efficiency and its influencing factors based on the EBM DEA model with undesirable outputs and spatial Durbin model
No full textThe threat of global climate change has caused the international community to pay close attention to atmospheric levels of greenhouse gases such as carbon dioxide. Transportation sector carbon dioxide emissions efficiency (TSCDEE) is a key indicator used to prioritize sustainable development in the transportation sector. In this paper, the epsilon-based measure data envelopment analysis model with undesirable outputs is applied to estimate TSCDEE for 30 provinces in China from 2010 to 2016. We also analyze influencing factors using the spatial Durbin model. Research shows that the overall TSCDEE of the Chinese provinces studied was 0.618, indicating that most regions are still in need of improvements. The provinces with the highest TSCDEE are located in developed coastal regions of China. This study shows that factors such as transportation structure, traffic infrastructure level, and technological progress have prominent positive effects on TSCDEE, while both urbanization level and urban population density exert significantly negative effects on TSCDEE. The findings should have a far-reaching impact on the sustainable development of global transportation.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Housing Quality and Process Innovatio
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