This mini-review summarizes some novel aspects of reactions conducted in aqueous/organic emulsions stabilized by carbon nanohybrids functionalized with catalytic species. Carbon nanohybrids represent a family of solid...This mini-review summarizes some novel aspects of reactions conducted in aqueous/organic emulsions stabilized by carbon nanohybrids functionalized with catalytic species. Carbon nanohybrids represent a family of solid catalysts that not only can stabilize water-oil emulsions in the same fashion as Pickering emulsions, but also catalyze reactions at the liquid/liquid interface. Several exam-ples are discussed in this mini-review. They include (a) aldol condensation-hydrodeoxygenation tandem reactions catalyzed by basic (MgO) and metal (Pd) catalysts, respectively; (b) Fischer-Tropsch synthesis catalyzed by carbon-nanotube-supported Ru; and (c) emulsion polymerization of styrene for the production of conductive polymer composites. Conducting these reactions in emul-sion generates important advantages, such as increased liquid/liquid interfacial area that consequently means faster mass transfer rates of molecules between the two phases, effective separation of products from the reaction mixture by differences in the water-oil solubility, and significant changes in product selectivity that can be adjusted by modifying the emulsion characteristics.展开更多
This paper analyzed the variations of latent heat flux (LHF) over the tropical Pacific in the period 1978-1988 by using COADS (Comprehensive Ocean and Atmospheric Data Set). It has been founded that the interannual va...This paper analyzed the variations of latent heat flux (LHF) over the tropical Pacific in the period 1978-1988 by using COADS (Comprehensive Ocean and Atmospheric Data Set). It has been founded that the interannual variabili ty of LHF exhibits strong ENSO signal, with the significant increasing LHF during the recent two warm events, i.e., 1982 / 83 and 1986 / 87 and decreasing LHF in the cold episodes. However the longitudinal distribution of the LHF departures varies from event to event. In the eastern Pacific, the specific humidity difference at air-sea interface (qs -qa) makes a dominant contribution to the interannual variability of LHF ( r = 0.73 ), while in the western Pacific the surface wind speed, W and the qs - qa make nearly equal contribution to that of LHF.展开更多
Background: The hepatic hemodynamics is an essential parameter in surgical planning as well as in various disease processes. The transit time ultrasound(TTUS) perivascular flow probe technology is widely used in clini...Background: The hepatic hemodynamics is an essential parameter in surgical planning as well as in various disease processes. The transit time ultrasound(TTUS) perivascular flow probe technology is widely used in clinical practice to evaluate the hepatic inflow, yet invasive. The phase-contrast-MRI(PC-MRI) is not invasive and potentially applicable in assessing the hepatic blood flow. In the present study, we compared the hepatic inflow rates using the PC-MRI and the TTUS probe, and evaluated their predictive value of post-hepatectomy adverse events. Methods: Eighteen large white pigs were anaesthetized for PC-MRI and approximately 75% hepatic resection was performed under a unified protocol. The blood flow was measured in the hepatic artery(Qha), the portal vein(Qpv), and the aorta above the celiac trunk(Qca) using PC-MRI, and was compared to the TTUS probe. The Bland-Altman method was conducted and a partial least squares regression(PLS) model was implemented. Results: The mean Qpv measured in PC-MRI was 0.55 ± 0.12 L/min, and in the TTUS probe was 0.74 ± 0.17 L/min. Qca was 1.40 ± 0.47 L/min in the PC-MRI and 2.00 ± 0.60 L/min in the TTUS probe. Qha was 0.17 ± 0.10 L/min in the PC-MRI, and 0.13 ± 0.06 L/min in the TTUS probe. The Bland-Altman method revealed that the estimated bias of Qca in the PC-MRI was 32%(95% CI:-49% to 15%); Qha 17%(95% CI:-15% to 51%); and Qpv 40%(95% CI:-62% to 18%). The TTUS probe had a higher weight in predicting adverse outcomes after 75% resection compared to the PC-MRI( β= 0.35 and 0.43 vs β = 0.22 and 0.07, for tissue changes and premature death, respectively). Conclusions: There is a tendency of the PC-MRI to underestimate the flow measured by the TTUS probes. The TTUS probe measures are more predictive of relevant post-hepatectomy outcomes.展开更多
The present work explores the reaction pathways of γ-valerolactone(GVL) over a supported ruthenium catalyst. The conversion of GVL in aqueous phase over a 5% Ru/C catalyst was investigated in a batch reactor operatin...The present work explores the reaction pathways of γ-valerolactone(GVL) over a supported ruthenium catalyst. The conversion of GVL in aqueous phase over a 5% Ru/C catalyst was investigated in a batch reactor operating at 463 K under 500–1000 psi of H2. The main reaction products obtained under these conditions were 2-butanol(2-BuOH), 1,4-pentanediol(1,4-PDO), 2-methyltetrahydrofuran(2-MTHF) and 2-pentanol(2-PeOH). A complete reaction network was developed, identifying the primary and/or secondary products. In this reaction network, production of 2-BuOH via decarbonylation of a ring-opened surface intermediate CH3CH(O*)–(CH2)2–CO*is clearly the dominant pathway. From the evolution of products as a function of reaction time and theoretical(DFT) calculations, a mechanism for the formation of intermediates and products is proposed. The high sensitivity of 2-BuOH production to the presence of CO, compared to a much lower effect on the production of the other products indicates that the sites responsible for decarbonylation are particularly prone to CO adsorption and poisoning. Also, since the decarbonylation rate is not affected by the H2 pressure it is concluded that the direct decarbonylation path of the CH3CH(O*)–(CH2)2–CO*intermediate does not required a previous dehydrogenation step, as is the case in decarbonylation of short alcohols.展开更多
To assess the adiabaticity of acoustic propagation in the ocean is very important for acoustic field calculation(forward problem) and tomographic retrieving (inverse problem). A new criterion of adiabaticity is propos...To assess the adiabaticity of acoustic propagation in the ocean is very important for acoustic field calculation(forward problem) and tomographic retrieving (inverse problem). A new criterion of adiabaticity is proposed recently (Shang et al., 2001). In this paper, numerical simulation has been conducted for acoustic propagation through the Polar Front to verify the new criterion. Numerical results on the f (frequency) -m (mode number) plan demonstrate that the new criterion works very well for this extremely non-gradual ocean structure.展开更多
The cleavage of the alkoxy(Ar-O-R) ether bond present in anisole is an interesting hydrodeoxygenation(HDO) reaction, since this asymmetric group contains two different C–O bonds, Caryl–O or Calkyl–O, which could po...The cleavage of the alkoxy(Ar-O-R) ether bond present in anisole is an interesting hydrodeoxygenation(HDO) reaction, since this asymmetric group contains two different C–O bonds, Caryl–O or Calkyl–O, which could potentially cleave. Recent work on the HDO of anisole over Pt, Ru, and Fe catalysts has shown that a common phenoxy surface intermediate is formed on all three metals. The subsequent reaction path of this intermediate varies from metal to metal, depending on the metal oxophilicity. Over the less oxophilic Pt, phenol is the only primary product. By contrast, on the more oxophilic Fe catalyst, the sole primary product is benzene instead of phenol. On Ru, with intermediate oxophilicity, both benzene and phenol are primary products. In this contribution, we have investigated Rh catalysts of varying surface nanostructures. A combination of experimental measurements and computational calculations was used to explore the effects of varying metal coordination number, an additional parameter that can be used to control the oxophilicity of a metal. The results confirm that metal oxophilicity is a good descriptor for HDO performance of metal catalysts and it can be controlled via selection of metal type and/or metal extent of coordination. Small Rh metal clusters with low coordination metal sites are more active for the deoxygenation pathway but also quickly deactivated while large clusters with high coordination sites are more active toward hydrogenation and more stable.展开更多
This paper assesses electoral participation and studies the determinants of such participation, focusing on presidential elections in Cote d＇Ivoire. We use a dataset on elections in Africa and a survey financed by th...This paper assesses electoral participation and studies the determinants of such participation, focusing on presidential elections in Cote d＇Ivoire. We use a dataset on elections in Africa and a survey financed by the European Commission and conducted by the Ivorian Center of Social and Economic Research （CIRES） in 2005. We find a decline in voter turnout since 1990 for both presidential and parliamentary elections. We also find that the probability of voting varies across ethnic groups and significantly increases with education levels, interest in politics, satisfaction with democracy and satisfaction with government but decreases with insecurity during elections. Moreover, we show that there is an inverted U-shaped relationship between age and the probability of voting. This probability is higher for men than women and for workers and retirees compared to unemployed, but it is low for students. Concerning the vote choice, we find that relative to the ＂program and party＂ criterion, the probability of choosing the candidate on the basis of his individual characteristics decreases with age, insecurity, satisfaction with democracy while it increases with satisfaction with government and with secondary, university or Koran education level.展开更多
<div style="text-align:justify;"> <span style="font-family:Verdana;">The aim of this work was to use fish processing waste (FW) as main substrate for anaerobic digestion. To enhance the...<div style="text-align:justify;"> <span style="font-family:Verdana;">The aim of this work was to use fish processing waste (FW) as main substrate for anaerobic digestion. To enhance the biogas production of FW, co-digestion was done with two other substrates: cow dung (CD) and waste of market (MW). Batch test was carried out in an 1</span><span "=""><span style="font-family:Verdana;"> L glass digester in a temperature controlled chamber at 38</span><span style="color:#4F4F4F;font-family:Verdana;">°</span><span style="font-family:Verdana;">C. The following mixtures were carried out: FW with CD respectively at different ratios 100:0% (A), 80:20%</span></span><span "=""> </span><span "="" style="font-family:Verdana;">(B) and 60:40% (C);FW with MW at the following ratio 80:20% (D);FW with CD and MW respectively at these ratios 80:10:10% (F) and 60:20:20% (G). The biogas produced was measured using a milligas counter</span><sup><span style="color:#4F4F4F;"><span style="color:#4F4F4F;font-family:Verdana;">®</span><span style="font-family:Verdana;"></span></span></sup><span "="" style="font-family:Verdana;"> and the volume of gas was recorded. The gas composition was determined using gas chromatography. With a pH stable for raw substrates and mixtures, TS and VS (%TS) contents for FW were respectively 31.01% and 91.55%. Between 3 to 13 days of experimentation, the highest flow rate was observed. The percentage of methane was more important for mixtures B and D, 61% and 59% respectively. pH and VOA/T</span><span "="" style="font-family:Verdana;">IC were stable at the end of the batch test for all mixtures, meaning that the organic matter was already well digested. The highest values of Volatile Solid Removal (VSR) were found for mixtures C, D, F and G. Therefore, the promising mixtures for next experimentations in large scale are B and D.</span> </div>展开更多
1. Overview The 2016 Quadrennial Ozone Symposium （QOS-2016） was held on 4-9 September 2016 in Edinburgh, UK. The Symposium was organized by the International Ozone Commission （IO3C）, the NERC Centre for Ecology ＆...1. Overview The 2016 Quadrennial Ozone Symposium （QOS-2016） was held on 4-9 September 2016 in Edinburgh, UK. The Symposium was organized by the International Ozone Commission （IO3C）, the NERC Centre for Ecology ＆ Hydrology and the University of Edinburgh, and was co-sponsored by the International Union of Geodesy and Geophysics, the International Association of Meteorology and Atmospheric Sciences, and the World Meteorological Organization.展开更多
近年来,分布式可再生能源以及智能终端大规模部署、数字孪生技术兴起以及市场化进程快速推进,虚拟电厂以及电动汽车等多元负荷带来多源异构数据的跨域协同,配电系统正经历着从“单一能量流”向“信息-能量融合”决策分析与调控的跨越,...近年来,分布式可再生能源以及智能终端大规模部署、数字孪生技术兴起以及市场化进程快速推进,虚拟电厂以及电动汽车等多元负荷带来多源异构数据的跨域协同,配电系统正经历着从“单一能量流”向“信息-能量融合”决策分析与调控的跨越,新时代下能源革命与数字革命的交汇催生了配电信息物理系统(cyber-physical distribution system,CPDS)的蓬勃发展。学术期刊中与此相关的理论研究、技术验证与工程实践成果层出不穷,各类论坛与产业峰会更是将“智能化”与“数字化”推向了前所未有的高度。展开更多
基金supported by the US Department of Energy/EPSCOR (DE SC00044136.85)
文摘This mini-review summarizes some novel aspects of reactions conducted in aqueous/organic emulsions stabilized by carbon nanohybrids functionalized with catalytic species. Carbon nanohybrids represent a family of solid catalysts that not only can stabilize water-oil emulsions in the same fashion as Pickering emulsions, but also catalyze reactions at the liquid/liquid interface. Several exam-ples are discussed in this mini-review. They include (a) aldol condensation-hydrodeoxygenation tandem reactions catalyzed by basic (MgO) and metal (Pd) catalysts, respectively; (b) Fischer-Tropsch synthesis catalyzed by carbon-nanotube-supported Ru; and (c) emulsion polymerization of styrene for the production of conductive polymer composites. Conducting these reactions in emul-sion generates important advantages, such as increased liquid/liquid interfacial area that consequently means faster mass transfer rates of molecules between the two phases, effective separation of products from the reaction mixture by differences in the water-oil solubility, and significant changes in product selectivity that can be adjusted by modifying the emulsion characteristics.
文摘This paper analyzed the variations of latent heat flux (LHF) over the tropical Pacific in the period 1978-1988 by using COADS (Comprehensive Ocean and Atmospheric Data Set). It has been founded that the interannual variabili ty of LHF exhibits strong ENSO signal, with the significant increasing LHF during the recent two warm events, i.e., 1982 / 83 and 1986 / 87 and decreasing LHF in the cold episodes. However the longitudinal distribution of the LHF departures varies from event to event. In the eastern Pacific, the specific humidity difference at air-sea interface (qs -qa) makes a dominant contribution to the interannual variability of LHF ( r = 0.73 ), while in the western Pacific the surface wind speed, W and the qs - qa make nearly equal contribution to that of LHF.
基金supported mainly by the “Agence de la Biomedecine” through its program of Research(AOR 2009)BM,AC,BP,WM,VCI and VE acknowledged funding of project ANR-13-TECS-0006 by the Agence Nationale de la Recherche
文摘Background: The hepatic hemodynamics is an essential parameter in surgical planning as well as in various disease processes. The transit time ultrasound(TTUS) perivascular flow probe technology is widely used in clinical practice to evaluate the hepatic inflow, yet invasive. The phase-contrast-MRI(PC-MRI) is not invasive and potentially applicable in assessing the hepatic blood flow. In the present study, we compared the hepatic inflow rates using the PC-MRI and the TTUS probe, and evaluated their predictive value of post-hepatectomy adverse events. Methods: Eighteen large white pigs were anaesthetized for PC-MRI and approximately 75% hepatic resection was performed under a unified protocol. The blood flow was measured in the hepatic artery(Qha), the portal vein(Qpv), and the aorta above the celiac trunk(Qca) using PC-MRI, and was compared to the TTUS probe. The Bland-Altman method was conducted and a partial least squares regression(PLS) model was implemented. Results: The mean Qpv measured in PC-MRI was 0.55 ± 0.12 L/min, and in the TTUS probe was 0.74 ± 0.17 L/min. Qca was 1.40 ± 0.47 L/min in the PC-MRI and 2.00 ± 0.60 L/min in the TTUS probe. Qha was 0.17 ± 0.10 L/min in the PC-MRI, and 0.13 ± 0.06 L/min in the TTUS probe. The Bland-Altman method revealed that the estimated bias of Qca in the PC-MRI was 32%(95% CI:-49% to 15%); Qha 17%(95% CI:-15% to 51%); and Qpv 40%(95% CI:-62% to 18%). The TTUS probe had a higher weight in predicting adverse outcomes after 75% resection compared to the PC-MRI( β= 0.35 and 0.43 vs β = 0.22 and 0.07, for tissue changes and premature death, respectively). Conclusions: There is a tendency of the PC-MRI to underestimate the flow measured by the TTUS probes. The TTUS probe measures are more predictive of relevant post-hepatectomy outcomes.
基金the Department of Energy for funding the experimental part of this work under grant DE-SC0004600the theoretical part under grant DE-EE0006287 of the Bioenergy Technology Office CHASE program
文摘The present work explores the reaction pathways of γ-valerolactone(GVL) over a supported ruthenium catalyst. The conversion of GVL in aqueous phase over a 5% Ru/C catalyst was investigated in a batch reactor operating at 463 K under 500–1000 psi of H2. The main reaction products obtained under these conditions were 2-butanol(2-BuOH), 1,4-pentanediol(1,4-PDO), 2-methyltetrahydrofuran(2-MTHF) and 2-pentanol(2-PeOH). A complete reaction network was developed, identifying the primary and/or secondary products. In this reaction network, production of 2-BuOH via decarbonylation of a ring-opened surface intermediate CH3CH(O*)–(CH2)2–CO*is clearly the dominant pathway. From the evolution of products as a function of reaction time and theoretical(DFT) calculations, a mechanism for the formation of intermediates and products is proposed. The high sensitivity of 2-BuOH production to the presence of CO, compared to a much lower effect on the production of the other products indicates that the sites responsible for decarbonylation are particularly prone to CO adsorption and poisoning. Also, since the decarbonylation rate is not affected by the H2 pressure it is concluded that the direct decarbonylation path of the CH3CH(O*)–(CH2)2–CO*intermediate does not required a previous dehydrogenation step, as is the case in decarbonylation of short alcohols.
文摘To assess the adiabaticity of acoustic propagation in the ocean is very important for acoustic field calculation(forward problem) and tomographic retrieving (inverse problem). A new criterion of adiabaticity is proposed recently (Shang et al., 2001). In this paper, numerical simulation has been conducted for acoustic propagation through the Polar Front to verify the new criterion. Numerical results on the f (frequency) -m (mode number) plan demonstrate that the new criterion works very well for this extremely non-gradual ocean structure.
基金supported by the U.S.Department of Energy,DOE/EPSCOR(Grant DESC0004600)
文摘The cleavage of the alkoxy(Ar-O-R) ether bond present in anisole is an interesting hydrodeoxygenation(HDO) reaction, since this asymmetric group contains two different C–O bonds, Caryl–O or Calkyl–O, which could potentially cleave. Recent work on the HDO of anisole over Pt, Ru, and Fe catalysts has shown that a common phenoxy surface intermediate is formed on all three metals. The subsequent reaction path of this intermediate varies from metal to metal, depending on the metal oxophilicity. Over the less oxophilic Pt, phenol is the only primary product. By contrast, on the more oxophilic Fe catalyst, the sole primary product is benzene instead of phenol. On Ru, with intermediate oxophilicity, both benzene and phenol are primary products. In this contribution, we have investigated Rh catalysts of varying surface nanostructures. A combination of experimental measurements and computational calculations was used to explore the effects of varying metal coordination number, an additional parameter that can be used to control the oxophilicity of a metal. The results confirm that metal oxophilicity is a good descriptor for HDO performance of metal catalysts and it can be controlled via selection of metal type and/or metal extent of coordination. Small Rh metal clusters with low coordination metal sites are more active for the deoxygenation pathway but also quickly deactivated while large clusters with high coordination sites are more active toward hydrogenation and more stable.
文摘This paper assesses electoral participation and studies the determinants of such participation, focusing on presidential elections in Cote d＇Ivoire. We use a dataset on elections in Africa and a survey financed by the European Commission and conducted by the Ivorian Center of Social and Economic Research （CIRES） in 2005. We find a decline in voter turnout since 1990 for both presidential and parliamentary elections. We also find that the probability of voting varies across ethnic groups and significantly increases with education levels, interest in politics, satisfaction with democracy and satisfaction with government but decreases with insecurity during elections. Moreover, we show that there is an inverted U-shaped relationship between age and the probability of voting. This probability is higher for men than women and for workers and retirees compared to unemployed, but it is low for students. Concerning the vote choice, we find that relative to the ＂program and party＂ criterion, the probability of choosing the candidate on the basis of his individual characteristics decreases with age, insecurity, satisfaction with democracy while it increases with satisfaction with government and with secondary, university or Koran education level.
文摘<div style="text-align:justify;"> <span style="font-family:Verdana;">The aim of this work was to use fish processing waste (FW) as main substrate for anaerobic digestion. To enhance the biogas production of FW, co-digestion was done with two other substrates: cow dung (CD) and waste of market (MW). Batch test was carried out in an 1</span><span "=""><span style="font-family:Verdana;"> L glass digester in a temperature controlled chamber at 38</span><span style="color:#4F4F4F;font-family:Verdana;">°</span><span style="font-family:Verdana;">C. The following mixtures were carried out: FW with CD respectively at different ratios 100:0% (A), 80:20%</span></span><span "=""> </span><span "="" style="font-family:Verdana;">(B) and 60:40% (C);FW with MW at the following ratio 80:20% (D);FW with CD and MW respectively at these ratios 80:10:10% (F) and 60:20:20% (G). The biogas produced was measured using a milligas counter</span><sup><span style="color:#4F4F4F;"><span style="color:#4F4F4F;font-family:Verdana;">®</span><span style="font-family:Verdana;"></span></span></sup><span "="" style="font-family:Verdana;"> and the volume of gas was recorded. The gas composition was determined using gas chromatography. With a pH stable for raw substrates and mixtures, TS and VS (%TS) contents for FW were respectively 31.01% and 91.55%. Between 3 to 13 days of experimentation, the highest flow rate was observed. The percentage of methane was more important for mixtures B and D, 61% and 59% respectively. pH and VOA/T</span><span "="" style="font-family:Verdana;">IC were stable at the end of the batch test for all mixtures, meaning that the organic matter was already well digested. The highest values of Volatile Solid Removal (VSR) were found for mixtures C, D, F and G. Therefore, the promising mixtures for next experimentations in large scale are B and D.</span> </div>
文摘1. Overview The 2016 Quadrennial Ozone Symposium （QOS-2016） was held on 4-9 September 2016 in Edinburgh, UK. The Symposium was organized by the International Ozone Commission （IO3C）, the NERC Centre for Ecology ＆ Hydrology and the University of Edinburgh, and was co-sponsored by the International Union of Geodesy and Geophysics, the International Association of Meteorology and Atmospheric Sciences, and the World Meteorological Organization.
文摘近年来,分布式可再生能源以及智能终端大规模部署、数字孪生技术兴起以及市场化进程快速推进,虚拟电厂以及电动汽车等多元负荷带来多源异构数据的跨域协同,配电系统正经历着从“单一能量流”向“信息-能量融合”决策分析与调控的跨越,新时代下能源革命与数字革命的交汇催生了配电信息物理系统(cyber-physical distribution system,CPDS)的蓬勃发展。学术期刊中与此相关的理论研究、技术验证与工程实践成果层出不穷,各类论坛与产业峰会更是将“智能化”与“数字化”推向了前所未有的高度。
