Oils and fats exist in many foods as emulsions, and preventing the oxidation of emulsion is vital importance for the food industry. In this study, the effect of different concentrations of Tween 20 (0.5, 2.5, 5.0, 10 ...Oils and fats exist in many foods as emulsions, and preventing the oxidation of emulsion is vital importance for the food industry. In this study, the effect of different concentrations of Tween 20 (0.5, 2.5, 5.0, 10 w% vs. oil) on the oxidation of canola oil O/W emulsion was investigated. Oxidation was conducted at 34°C in the dark and accelerated using 2,2-azobis (2,4-dimethylvaleronitrile) (AMVN) and 2,2’-azobis (2-methylpropionamidine) dihydrochloride (AAPH) as radical generators. Peroxide value (PV, mEq/kg) was monitored as generation of the primary oxidation compound. PV was suppressed by Tween 20 in a dose-dependent manner in both emulsion system using AMVN and AAPH, and the tendency of suppression was clearer in the system using AMVN than in that using AAPH. Contrarily, there were no significant differences in PV when emulsions were prepared with tocopherol-stripped oil. The particle size of emulsion droplets were also consistent among emulsions prepared. However, tocopherol contents at lipid phase of the emulsions prior to oxidation decreased with concentration of Tween 20. These results suggest that excess Tween 20 could cause tocopherol to migrate from the lipid phase of the emulsions to lipid-oil interface, suppressing the oxidation of emulsions.展开更多
Hydrazine oxidation reaction(HzOR)assisted hydrogen evolution reaction(HER)offers a feasible path for low power consumption to hydrogen production.Unfortunately however,the total electrooxidation of hydrazine in anode...Hydrazine oxidation reaction(HzOR)assisted hydrogen evolution reaction(HER)offers a feasible path for low power consumption to hydrogen production.Unfortunately however,the total electrooxidation of hydrazine in anode and the dissociation kinetics of water in cathode are critically depend on the interaction between the reaction intermediates and surface of catalysts,which are still challenging due to the totally different catalytic mechanisms.Herein,the[W–O]group with strong adsorption capacity is introduced into CoP nanoflakes to fabricate bifunctional catalyst,which possesses excellent catalytic performances towards both HER(185.60 mV at 1000 mA cm^(−2))and HzOR(78.99 mV at 10,00 mA cm^(−2))with the overall electrolyzer potential of 1.634 V lower than that of the water splitting system at 100 mA cm^(−2).The introduction of[W–O]groups,working as the adsorption sites for H2O dissociation and N2H4 dehydrogenation,leads to the formation of porous structure on CoP nanoflakes and regulates the electronic structure of Co through the linked O in[W–O]group as well,resultantly boosting the hydrogen production and HzOR.Moreover,a proof-of-concept direct hydrazine fuel cell-powered H_(2) production system has been assembled,realizing H_(2)evolution at a rate of 3.53 mmol cm^(−2)h^(−1)at room temperature without external electricity supply.展开更多
Although hydrophilic membranes are desired for reducing resistance to water permeation, hydrophilic surfaces are not used in the water-in-oil(W/O) membrane emulsification process because water spreads on the hydrophil...Although hydrophilic membranes are desired for reducing resistance to water permeation, hydrophilic surfaces are not used in the water-in-oil(W/O) membrane emulsification process because water spreads on the hydrophilic surface without forming droplets. Here, we report that a hydrophilic ceramic membrane can form a hydrophobic interface in diesel at a higher temperature;interestingly, the experiments show that the contact angle increases when the temperature rises. The hydrophilic membrane surface evolves into a hydrophobic interface, particularly near the boiling point of water, resulting in a water contact angle of 147.5° ± 1.2°. This work established a method for preparing W/O monodispersed emulsions by direct emulsification of hydrophilic ceramic membranes at a temperature close to the boiling point of water.Additionally, it made high flux of membrane emulsification of monodispersed W/O emulsions possible,which satisfied the industrial requirements of fluidized catalytic cracking in the petrochemical industry.展开更多
A new reactor with integrated conventional slurry stirred reactor and ceramic external membrane emulsification system, was introduced in this paper. Toluene and toluene containing surfactant was separately used as dis...A new reactor with integrated conventional slurry stirred reactor and ceramic external membrane emulsification system, was introduced in this paper. Toluene and toluene containing surfactant was separately used as dispersed phase for preparation of emulsions. Two kinds of emulsions were prepared and compared. The volume average sizes of prepared emulsions were 3.53μm and 3.6μm respectively. The results showed that the droplet sizes of two kinds of emulsions were similar, but the monodispersed emulsion was only obtained with addition of surfactant into the dispersed phase.展开更多
The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration o...The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration of surfactant,C<sub>2</sub>,can be estimated by Eq.（7）—（9）.The swelling caused by emulsification during the initial dispersion process was investigated.The swelling rate wasmeasured by a density method.A model for estimating the"Emulsification" swelling rate,F<sub>se</sub>,has been proposed,basedon a mechanism of swelling due to the entrainment of water resulted from the interracial turbulence and emulsification inthe initial dispersion process.It has been found that Eq.（26）gives excellent fit to the experimental data of Fujinawa,etal.and of the authors.展开更多
Low-speed rotation of disc in an internal circulation of a novel de-emulsification with rotation-dise horizental contactor(RHC-D) realized de-emulsification for O/W emulsions due to repeated coalescence in oil-wet nar...Low-speed rotation of disc in an internal circulation of a novel de-emulsification with rotation-dise horizental contactor(RHC-D) realized de-emulsification for O/W emulsions due to repeated coalescence in oil-wet narrow channels at a low rotation speed. For three emulsions included ethanol/water/2-ethyl-1-hexanol, ethanol/water/2-ethyl-1-hexanol/SDS(Sodium Dodecyl Sulfonate) and 2-ethyl-1-hexanol/water/SDS emulsion, deemulsification ratios of oil phase could reach 1, 1 and 0.67 respectively at 170 r·min-1, and de-emulsification ratios increased obviously after agitating 10 min. De-emulsification experiment in the seam indicated that oil droplet sizes in O/W emulsion became larger after de-emulsification. The main de-emulsification mechanism in RHCD was the coalescence of oil droplets in oil-wet narrow channels. With increase of the rotation speed, oil droplets dispersed better in the aqueous phase. However, de-emulsification effect enhanced due to the increase of the coalescence rate at a bit higher rotation speed. In addition, internal circulation made those O/W emulsions to be broken repeatedly, consequently de-emulsification ratio increased. Repeated de-emulsification through internal circulation might make continuous extraction of ethanol come true at a low rotation speed.展开更多
The massive vector bosons Z o, W ± and the scalar Higgs-boson H o assumed in weak interaction theory, but also the six quarks required in strong interactions are well understood in an alternative quantum field th...The massive vector bosons Z o, W ± and the scalar Higgs-boson H o assumed in weak interaction theory, but also the six quarks required in strong interactions are well understood in an alternative quantum field theory of fermions and bosons: Z o and W ± as well as all quark-antiquark states (here only the tt¯state is discussed) are described by bound states with scalar coupling between their massless constituents and have a structure similar to leptons. However, the scalar Higgs-boson H o corresponds to a state with vector coupling between the elementary constituents. Similar scalar states are expected also in the mass region of the mesons ω (0.782 GeV) - Υ ( 9.46 GeV). The underlying calculations can be run on line using the Web-address https://h2909473.stratoserver.net.展开更多
The stabilizing conditions of W/O microemulsion of Tx 6～C 4H 9OH/c C 6H 12 /H 2O system were studied by visual observation and electrical conductance.The result shows that when the weight ratio of Tx 6 and C 4H 9OH i...The stabilizing conditions of W/O microemulsion of Tx 6～C 4H 9OH/c C 6H 12 /H 2O system were studied by visual observation and electrical conductance.The result shows that when the weight ratio of Tx 6 and C 4H 9OH is 4∶1,the W/O microemulsion sytem has stabilizing and extensive regions,and the system is insensitive to the values of pH at room temperature.In accordance with the theoretical value of HLB,the suitable value of HLB for Tx 6 and C 4H 9OH to compose microemulsion is greater than 9,less than or equal to 10.展开更多
文摘Oils and fats exist in many foods as emulsions, and preventing the oxidation of emulsion is vital importance for the food industry. In this study, the effect of different concentrations of Tween 20 (0.5, 2.5, 5.0, 10 w% vs. oil) on the oxidation of canola oil O/W emulsion was investigated. Oxidation was conducted at 34°C in the dark and accelerated using 2,2-azobis (2,4-dimethylvaleronitrile) (AMVN) and 2,2’-azobis (2-methylpropionamidine) dihydrochloride (AAPH) as radical generators. Peroxide value (PV, mEq/kg) was monitored as generation of the primary oxidation compound. PV was suppressed by Tween 20 in a dose-dependent manner in both emulsion system using AMVN and AAPH, and the tendency of suppression was clearer in the system using AMVN than in that using AAPH. Contrarily, there were no significant differences in PV when emulsions were prepared with tocopherol-stripped oil. The particle size of emulsion droplets were also consistent among emulsions prepared. However, tocopherol contents at lipid phase of the emulsions prior to oxidation decreased with concentration of Tween 20. These results suggest that excess Tween 20 could cause tocopherol to migrate from the lipid phase of the emulsions to lipid-oil interface, suppressing the oxidation of emulsions.
基金support of this research by National Natural Science Foundation of China(52172110)Key Research Program of Frontier Sciences,Chinese Academy of Sciences(ZDBS-LY-SLH029)+1 种基金the“Scientific and Technical Innovation Action Plan”Hong Kong,Macao and Taiwan Science&Technology Cooperation Project of Shanghai Science and Technology Committee(21520760500)BL14W1 beamline of Shanghai Synchrotron Radiation Facility(SSRF).
文摘Hydrazine oxidation reaction(HzOR)assisted hydrogen evolution reaction(HER)offers a feasible path for low power consumption to hydrogen production.Unfortunately however,the total electrooxidation of hydrazine in anode and the dissociation kinetics of water in cathode are critically depend on the interaction between the reaction intermediates and surface of catalysts,which are still challenging due to the totally different catalytic mechanisms.Herein,the[W–O]group with strong adsorption capacity is introduced into CoP nanoflakes to fabricate bifunctional catalyst,which possesses excellent catalytic performances towards both HER(185.60 mV at 1000 mA cm^(−2))and HzOR(78.99 mV at 10,00 mA cm^(−2))with the overall electrolyzer potential of 1.634 V lower than that of the water splitting system at 100 mA cm^(−2).The introduction of[W–O]groups,working as the adsorption sites for H2O dissociation and N2H4 dehydrogenation,leads to the formation of porous structure on CoP nanoflakes and regulates the electronic structure of Co through the linked O in[W–O]group as well,resultantly boosting the hydrogen production and HzOR.Moreover,a proof-of-concept direct hydrazine fuel cell-powered H_(2) production system has been assembled,realizing H_(2)evolution at a rate of 3.53 mmol cm^(−2)h^(−1)at room temperature without external electricity supply.
基金the support from the National Key Research and Development Program of China (2021YFB3801303)the National Natural Science Foundation of China (21838005, 21921006)the Key Scientific Research and Development Projects of Jiangsu Province (BE201800901)。
文摘Although hydrophilic membranes are desired for reducing resistance to water permeation, hydrophilic surfaces are not used in the water-in-oil(W/O) membrane emulsification process because water spreads on the hydrophilic surface without forming droplets. Here, we report that a hydrophilic ceramic membrane can form a hydrophobic interface in diesel at a higher temperature;interestingly, the experiments show that the contact angle increases when the temperature rises. The hydrophilic membrane surface evolves into a hydrophobic interface, particularly near the boiling point of water, resulting in a water contact angle of 147.5° ± 1.2°. This work established a method for preparing W/O monodispersed emulsions by direct emulsification of hydrophilic ceramic membranes at a temperature close to the boiling point of water.Additionally, it made high flux of membrane emulsification of monodispersed W/O emulsions possible,which satisfied the industrial requirements of fluidized catalytic cracking in the petrochemical industry.
基金the National Basic Research Program of China (No. 2003CB615700) the National Natural Science Foundation of China (No. 20125618).
文摘A new reactor with integrated conventional slurry stirred reactor and ceramic external membrane emulsification system, was introduced in this paper. Toluene and toluene containing surfactant was separately used as dispersed phase for preparation of emulsions. Two kinds of emulsions were prepared and compared. The volume average sizes of prepared emulsions were 3.53μm and 3.6μm respectively. The results showed that the droplet sizes of two kinds of emulsions were similar, but the monodispersed emulsion was only obtained with addition of surfactant into the dispersed phase.
文摘The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration of surfactant,C<sub>2</sub>,can be estimated by Eq.（7）—（9）.The swelling caused by emulsification during the initial dispersion process was investigated.The swelling rate wasmeasured by a density method.A model for estimating the"Emulsification" swelling rate,F<sub>se</sub>,has been proposed,basedon a mechanism of swelling due to the entrainment of water resulted from the interracial turbulence and emulsification inthe initial dispersion process.It has been found that Eq.（26）gives excellent fit to the experimental data of Fujinawa,etal.and of the authors.
文摘Low-speed rotation of disc in an internal circulation of a novel de-emulsification with rotation-dise horizental contactor(RHC-D) realized de-emulsification for O/W emulsions due to repeated coalescence in oil-wet narrow channels at a low rotation speed. For three emulsions included ethanol/water/2-ethyl-1-hexanol, ethanol/water/2-ethyl-1-hexanol/SDS(Sodium Dodecyl Sulfonate) and 2-ethyl-1-hexanol/water/SDS emulsion, deemulsification ratios of oil phase could reach 1, 1 and 0.67 respectively at 170 r·min-1, and de-emulsification ratios increased obviously after agitating 10 min. De-emulsification experiment in the seam indicated that oil droplet sizes in O/W emulsion became larger after de-emulsification. The main de-emulsification mechanism in RHCD was the coalescence of oil droplets in oil-wet narrow channels. With increase of the rotation speed, oil droplets dispersed better in the aqueous phase. However, de-emulsification effect enhanced due to the increase of the coalescence rate at a bit higher rotation speed. In addition, internal circulation made those O/W emulsions to be broken repeatedly, consequently de-emulsification ratio increased. Repeated de-emulsification through internal circulation might make continuous extraction of ethanol come true at a low rotation speed.
文摘The massive vector bosons Z o, W ± and the scalar Higgs-boson H o assumed in weak interaction theory, but also the six quarks required in strong interactions are well understood in an alternative quantum field theory of fermions and bosons: Z o and W ± as well as all quark-antiquark states (here only the tt¯state is discussed) are described by bound states with scalar coupling between their massless constituents and have a structure similar to leptons. However, the scalar Higgs-boson H o corresponds to a state with vector coupling between the elementary constituents. Similar scalar states are expected also in the mass region of the mesons ω (0.782 GeV) - Υ ( 9.46 GeV). The underlying calculations can be run on line using the Web-address https://h2909473.stratoserver.net.
文摘The stabilizing conditions of W/O microemulsion of Tx 6～C 4H 9OH/c C 6H 12 /H 2O system were studied by visual observation and electrical conductance.The result shows that when the weight ratio of Tx 6 and C 4H 9OH is 4∶1,the W/O microemulsion sytem has stabilizing and extensive regions,and the system is insensitive to the values of pH at room temperature.In accordance with the theoretical value of HLB,the suitable value of HLB for Tx 6 and C 4H 9OH to compose microemulsion is greater than 9,less than or equal to 10.
