To conduct extensive research on the application of ionic liquids as collectors in mineral flotation,ethanol(EtOH)was used as a solvent to dissolve hydrophobic ionic liquids(ILs)to simplify the reagent regime.Interest...To conduct extensive research on the application of ionic liquids as collectors in mineral flotation,ethanol(EtOH)was used as a solvent to dissolve hydrophobic ionic liquids(ILs)to simplify the reagent regime.Interesting phenomena were observed in which EtOH exerted different effects on the flotation efficiency of two ILs with similar structures.When EtOH was used to dissolve 1-dodecyl-3-methylimidazolium chloride(C12[mim]Cl)and as a collector for pure quartz flotation tests at a concentration of 1×10^(−5)mol·L^(−1),quartz recovery increased from 23.77%to 77.91%compared with ILs dissolved in water.However,quartz recovery of 1-dodecyl-3-methylim-idazolium hexafluorophosphate(C12[mim]PF6)decreased from 60.45%to 24.52%under the same conditions.The conditional experi-ments under 1×10^(−5)mol·L^(−1)ILs for EtOH concentration and under 2vol%EtOH for ILs concentration confirmed this difference.After being affected by EtOH,the mixed ore flotation tests of quartz and hematite showed a decrease in the hematite concentrate grade and re-covery for the C12[mim]Cl collector,whereas the hematite concentrate grade and recovery for the C12[mim]PF6 collector increased.On the basis of these differences and observations of flotation foam,two-phase bubble observation tests were carried out.The EtOH promoted the foam height of two ILs during aeration.It accelerated static froth defoaming after aeration stopped,and the foam of C12[mim]PF6 de-foaming especially quickly.In the discussion of flotation tests and foam observation,an attempt was made to explain the reasons and mechanisms behind the diverse phenomena using the dynamic surface tension effect and solvation effect results from EtOH.The solva-tion effect was verified through Fourier transform infrared(FT-IR),X-ray photoelectron spectroscopy(XPS),and Zeta potential tests.Al-though EtOH affects the adsorption of ILs on the ore surface during flotation negatively,it holds an positive value of inhibiting foam mer-ging during flotation aeration and accelerating the defoaming of static foam.And induce more robust secondary enrichment in the mixed ore flotation of the C12[mim]PF6 collector,facilitating effective mixed ore separation even under inhibitor-free conditions.展开更多
A thermodynamic model was developed for determining the surface tension of RE2O3-MgO-SiO2(RE=La, Nd, Sm, Gd and Y) melts considering the ionic radii of the components and Butler's equation. The temperature and com...A thermodynamic model was developed for determining the surface tension of RE2O3-MgO-SiO2(RE=La, Nd, Sm, Gd and Y) melts considering the ionic radii of the components and Butler's equation. The temperature and composition dependence of the surface tensions in molten RE2O3-MgO-SiO2 slag systems was reproduced by the present model using surface tensions and molar volumes of pure oxides, as well as the anionic and cationic radii of the melt components. The iso-surface tension lines of La2O3-MgO-SiO2 slag melt at 1873 K were calculated and the effects of slag composition on the surface tension were also investigated. The surface tensions of La2O3, Gd2O3, Nd2O3 and Y2O3 at 1873 K were evaluated as 686, 677, 664 and 541 m N/m, respectively. The surface tension of pure rare earth oxide melts linearly decreases with increasing cationic field strength, except for Y2O3 oxide, while Y2O3 has a much weaker surface tension. The evaluated results of the surface tension show good agreements with literature data, and the mean deviation of the present model is found to be 1.05% at 1873 K.展开更多
Aiming at the process of smelting ultra-high(>80%)or even full vanadium titanomagnetite in blast furnace,we are conducting a series of works on physics character of high TiO_(2) bearing blast furnace slag(BFS)for s...Aiming at the process of smelting ultra-high(>80%)or even full vanadium titanomagnetite in blast furnace,we are conducting a series of works on physics character of high TiO_(2) bearing blast furnace slag(BFS)for slag optimization.This work discussed the density and surface tension of high TiO_(2) bearing BFS using the Archimedean principle and the maximum bubble pressure method,respectively.The influence of TiO_(2) content and the MgO/CaO mass ratio on the density and surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3)slags were investigated Results indicated that the density of slags decreased with the TiO_(2) content increasing from 20wt%to 30wt%,but it increased slightly with the MgO/CaO mass ratio increasing from 0.32 to 0.73.In view of silicate network structure,the density and the degree of polymerization(DOP)of network structure have a consistent trend.The addition of TiO_(2) reduced(Q^(3))^(2)/(Q^(2)) ratio(Q^(2) and Q^(3) represent structural unit with bridge oxygen number of 2 and 3,respectively)and then decreased DOP,which led to the decrease of slag density.The surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3) slags decreased dramatically with the TiO_(2) content increasing from 20wt%to 30wt%.Conversely,it increased with the MgO/CaO mass ratio increasing from 0.32 to 0.73.Furthermore,the iso-surface tension lines were obtained under 1723 K using the Tanaka developed model in view of Butler formula.It may be useful for slag optimization of ultra-high proportion(>80%)or even full vanadium titanomagnetite under BF smelting.展开更多
Based on the coexistence theory of slag melt structure and Butler’s equation,a new calculation model has been proposed for the calculation of surface tension of slag melt.This model establishes a specific correlation...Based on the coexistence theory of slag melt structure and Butler’s equation,a new calculation model has been proposed for the calculation of surface tension of slag melt.This model establishes a specific correlation between surface tension and mass action concentrations(activities) in the melt and on its surface on the basis of inner and surficial structures of slag melt.Calculated surface tensions of CaO-SiOand MnO-SiOslag melts are consistent with those measured.Furthermore,iso-surface tension lines of CaO-MnO-SiOslag melt have also been calculated.展开更多
The densities and surface tensions of [Bmim][TFO]/H2SO4, [Hmim][TFO]/H2SO4 and [Omim][TFO]/H2SO4 binary mixtures were measured by pycnometer and Wilhelmy plate method respectively. The results show that densities and ...The densities and surface tensions of [Bmim][TFO]/H2SO4, [Hmim][TFO]/H2SO4 and [Omim][TFO]/H2SO4 binary mixtures were measured by pycnometer and Wilhelmy plate method respectively. The results show that densities and surface tensions of the mixtures decreased monotonously with increasing temperatures and increasing ionic liquid （IL） molar fraction. IL with longer alkyl side-chain length brings a lower density and a smaller surface tension to the ILs/H2SO4 binary mixtures. The densities and surface tensions of the mixtures are fitted well by Jouyban-Acree （JAM） model and LWW model respectively. Redlich-Kister （R-K）equation and modified Redlich-Kister （R-K） equation describe the excess molar volumes and excess surface tensions of the mixtures well respectively. Adding a small amount of ILs （XIL 〈 0.1 ） into sulfuric acid brings an obvious decrease to the density and the surface tension. The results imply that the densities and surface tensions of IL5/H2SO4 binary mixtures can be modulated by changing the IL dosage or tailoring the IL structure.展开更多
Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface te...Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface tensions were calculated from crystallization induction times using classic homogeneous nucleation theory. Induction time and surface tension decreased at higher temperature.展开更多
In order to investigate the effect of additives and nano-particle on the surface tensions of lithium bromide(Li Br) aqueous solution/ammonia, many experiments were carried out based on Wilhelmy plate method. Firstly, ...In order to investigate the effect of additives and nano-particle on the surface tensions of lithium bromide(Li Br) aqueous solution/ammonia, many experiments were carried out based on Wilhelmy plate method. Firstly, the surface tension of Li Br aqueous solution with 1-octanol was measured and then the comparison between the measured results and previous experimental results was given to verify the measuring accuracy. Some new additives, such as cationic surfactants cetyltrimethyl ammonium chloride(CTAC), and cetyltrimethyl ammonium bromide(CTAB) were chosen in the experiments. The experimental results show that CTAC and CTAB can obviously reduce the surface tension of Li Br aqueous solution/ammonia. In addition, it is found that nano-particles cannot remarkably decrease the surface tension of Li Br aqueous solution/ammonia. However, the mixed addition of additives and nano-particles can remarkably affect the surface tension of Li Br aqueous solution/ammonia. That is to say, additives play more important role in reducing the surface tension of Li Br aqueous solution/ammonia. But nano-particles may enhance the heat transfer in the absorption refrigeration process.展开更多
Phase field investigation reveals that the stability of the planar interface is related to the anisotropic intensity of surface tension and the misorientation of preferred crystallographic orientation with respect to ...Phase field investigation reveals that the stability of the planar interface is related to the anisotropic intensity of surface tension and the misorientation of preferred crystallographic orientation with respect to the heat flow direction. The large anisotropic intensity may compete to determine the stability of the planar interface. The destabilizing effect or the stabilizing effect depends on the misorientation. Moreover, the interface morphology of initial instability is also affected by the surface tension anisotropy.展开更多
Surface tension of molten IF steel containing Ti and contact angle between the liquid steel and solid alumina were measured with sessile droplet method under Ar gas atmosphere at 1500, 1575 and 1600°C. The result...Surface tension of molten IF steel containing Ti and contact angle between the liquid steel and solid alumina were measured with sessile droplet method under Ar gas atmosphere at 1500, 1575 and 1600°C. The results show that titanium decreases the surface tension of the molten IF steel and the contact angle. The interfacial tension between the molten IF steel containing Ti and solid alumina decreases with increase in titanium content. The work of adhesion between molten IF steel containing Ti and solid alumina decreases slightly at 1550°C, but increases at 1600°C with increasing titanium content. It can be deduced that fine bubbles and fine alumina inclusions are easily entrapped in solidifying interface for IF steel containing Ti.展开更多
The surface tension of a promising lead-free solder Au-Bi-Sn alloys was investigated both by the sessile-drop method and calculation. Experimental measurements were carried out for two cross-sections with the constant...The surface tension of a promising lead-free solder Au-Bi-Sn alloys was investigated both by the sessile-drop method and calculation. Experimental measurements were carried out for two cross-sections with the constant gold to bismuth ration of 1:1 and 1:2. For all the investigated compositions, decrease of the surface tension is observed with increasing temperature. Meanwhile, the surface tension values were also calculated based on Butler’s equation, with using the newest research on thermodynamics data of Au-Bi-Sn ternary system. Compared with the experimental results, a good agreement was obtained.展开更多
Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively....Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid circulation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid velocity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.展开更多
Surface roughness is an important factor that affects the wetting of molten metal on ceramics.The effect of surface roughness of the alumina substrate on the contact angle,contact diameter,drop height and surface tens...Surface roughness is an important factor that affects the wetting of molten metal on ceramics.The effect of surface roughness of the alumina substrate on the contact angle,contact diameter,drop height and surface tension of molten lead was investigated in the temperature range of 923-1123 K.The microstructure of the lead/substrate interface was observed by SEM.The surface free energy of alumina substrates was calculated by the geometrical average method.When the surface roughness of the substrate increased from 0.092 to 2.23μm,the surface free energy increased gradually,ranging from 13.356 to 39.998 mJ/m^(2).The contact diameter of lead droplets decreased from 9.111 to 7.19 mm.The lead drop height increased from 3.41 to 3.85 mm.The contact angle increased from 113.05°to 137.15°.Moreover,the surface depression of the alumina substrate was filled with lead,and no obvious change was observed.The results demonstrated that the wetting of lead drop on alumina substrates was consistent with the Wenzel state.展开更多
A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. Th...A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.展开更多
Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensio...Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensions of liquid stable and undercooled Ni-Cu (x(Ni)=0.42) and Ni-Fe (x(Ni)=0.3 and 0.7) alloys are calculated using STCBE (Surface Tension Calculation based on Butler Equation) program. The agreement between calculated values and experimental data is good enough, and the temperature dependence of the surface tension can be reasonable down to 150-200 K under the liquid temperature of the alloys.展开更多
The equation of state(EOS)for square-well chain fluid with variable range(SWCF-VR) developed in our previous work based on statistical mechanical theory for chemical association is employed for the correlations of sur...The equation of state(EOS)for square-well chain fluid with variable range(SWCF-VR) developed in our previous work based on statistical mechanical theory for chemical association is employed for the correlations of surface tension and viscosity of common fluids and ionic liquids(ILs).A model of surface tension for multi-component mixtures is presented by combining the SWCF-VR EOS and the scaled particle theory and used to produce the surface tension of binary and ternary mixtures.The predicted surface tensions are in excellent agreement with the experimental data with an overall average absolute relative deviation(AAD)of 0.36%.A method for the calculation of dynamic viscosity of common fluids and ILs at high pressure is presented by combining Eyring’s rate theory of viscosity and the SWCF-VR EOS.The calculated viscosities are in good agreement with the experimental data with the overall AAD of 1.44% for 14 fluids in 84 cases.The salient feature is that the molecular parameters used in these models are self-consistent and can be applied to calculate different thermodynamic properties such as pVT,vapor-liquid equilibrium,caloric properties,surface tension,and viscosity.展开更多
In molten phase metallurgical processes,mixing via gas injection has a vital role in obtaining a homogeneous product.The efficiency of mixing depends on operational variables such as gas flow rate and slag height as w...In molten phase metallurgical processes,mixing via gas injection has a vital role in obtaining a homogeneous product.The efficiency of mixing depends on operational variables such as gas flow rate and slag height as well as physical properties of the molten phases.A numerical simulation is conducted to study the above parameters in the flow behavior of a bottom-blown bath.The molten metal and the slag are modeled by water and oil,respectively.The numerical results,particularly the mixing time,are validated against experimental data.The results show that mixing time increases as the slag height increases and decreases as the density of the slag material increases.The mixing time decreases with an increase in the density of the primary phase;however,it increases as the surface tension between air and water increases.A case with properties close to a real molten metal is also modeled.The performance of the system is influenced by the momentum rather than the dissipative forces.Thus,the effect of the density of the molten phase on the mixing process is more pronounced compared to the effect of the surface tension between the air and the molten phase.展开更多
A new equation for predicting surface tension is proposed based on the thermodynamic definition of surface tension and the expression of the Gibbs free energy of the system. Using the NRTL equation to represent the ex...A new equation for predicting surface tension is proposed based on the thermodynamic definition of surface tension and the expression of the Gibbs free energy of the system. Using the NRTL equation to represent the excess Gibbs free energy, a two-parameter surface tension equation is derived. The feasibility of the new equation has been tested in terms of 124 binary and 16 multicomponent systems(13-ternary and 3-quaternary) with absolute relative deviations of 0.59% and 1.55% respectively. This model is also predictive for the temperature dependence of surface tension of liquid mixtures. It is shown that, with good accuracy, this equation is simple and reliable for practical use.展开更多
Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydrox...Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.展开更多
A setup for recording surface tension curves at a mercury drop during potential scanning is designed based on photo-sensitive detection system. Surface tension spectrum at Hg drop can be recorded by voltam0metdc study...A setup for recording surface tension curves at a mercury drop during potential scanning is designed based on photo-sensitive detection system. Surface tension spectrum at Hg drop can be recorded by voltam0metdc study. A Yb（Ⅲ）-NO2 catalytic reduction system was used for characterization. The simple, sensitive technique can be expected to provide fresh information on molecular interactions at electrode surfaces.展开更多
基金supported by the National Natural Science Foundation of China(No.51874221)the Open Foundation of Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Materials,Guangxi University(No.2022GXYSOF 11).
文摘To conduct extensive research on the application of ionic liquids as collectors in mineral flotation,ethanol(EtOH)was used as a solvent to dissolve hydrophobic ionic liquids(ILs)to simplify the reagent regime.Interesting phenomena were observed in which EtOH exerted different effects on the flotation efficiency of two ILs with similar structures.When EtOH was used to dissolve 1-dodecyl-3-methylimidazolium chloride(C12[mim]Cl)and as a collector for pure quartz flotation tests at a concentration of 1×10^(−5)mol·L^(−1),quartz recovery increased from 23.77%to 77.91%compared with ILs dissolved in water.However,quartz recovery of 1-dodecyl-3-methylim-idazolium hexafluorophosphate(C12[mim]PF6)decreased from 60.45%to 24.52%under the same conditions.The conditional experi-ments under 1×10^(−5)mol·L^(−1)ILs for EtOH concentration and under 2vol%EtOH for ILs concentration confirmed this difference.After being affected by EtOH,the mixed ore flotation tests of quartz and hematite showed a decrease in the hematite concentrate grade and re-covery for the C12[mim]Cl collector,whereas the hematite concentrate grade and recovery for the C12[mim]PF6 collector increased.On the basis of these differences and observations of flotation foam,two-phase bubble observation tests were carried out.The EtOH promoted the foam height of two ILs during aeration.It accelerated static froth defoaming after aeration stopped,and the foam of C12[mim]PF6 de-foaming especially quickly.In the discussion of flotation tests and foam observation,an attempt was made to explain the reasons and mechanisms behind the diverse phenomena using the dynamic surface tension effect and solvation effect results from EtOH.The solva-tion effect was verified through Fourier transform infrared(FT-IR),X-ray photoelectron spectroscopy(XPS),and Zeta potential tests.Al-though EtOH affects the adsorption of ILs on the ore surface during flotation negatively,it holds an positive value of inhibiting foam mer-ging during flotation aeration and accelerating the defoaming of static foam.And induce more robust secondary enrichment in the mixed ore flotation of the C12[mim]PF6 collector,facilitating effective mixed ore separation even under inhibitor-free conditions.
基金Project(51374020)supported by the National Natural Science Foundation of China
文摘A thermodynamic model was developed for determining the surface tension of RE2O3-MgO-SiO2(RE=La, Nd, Sm, Gd and Y) melts considering the ionic radii of the components and Butler's equation. The temperature and composition dependence of the surface tensions in molten RE2O3-MgO-SiO2 slag systems was reproduced by the present model using surface tensions and molar volumes of pure oxides, as well as the anionic and cationic radii of the melt components. The iso-surface tension lines of La2O3-MgO-SiO2 slag melt at 1873 K were calculated and the effects of slag composition on the surface tension were also investigated. The surface tensions of La2O3, Gd2O3, Nd2O3 and Y2O3 at 1873 K were evaluated as 686, 677, 664 and 541 m N/m, respectively. The surface tension of pure rare earth oxide melts linearly decreases with increasing cationic field strength, except for Y2O3 oxide, while Y2O3 has a much weaker surface tension. The evaluated results of the surface tension show good agreements with literature data, and the mean deviation of the present model is found to be 1.05% at 1873 K.
基金financially supported by the National Key R&D Program of China(No.2018YFC1900500)the Key Fund of Natural Science(No.51974048)。
文摘Aiming at the process of smelting ultra-high(>80%)or even full vanadium titanomagnetite in blast furnace,we are conducting a series of works on physics character of high TiO_(2) bearing blast furnace slag(BFS)for slag optimization.This work discussed the density and surface tension of high TiO_(2) bearing BFS using the Archimedean principle and the maximum bubble pressure method,respectively.The influence of TiO_(2) content and the MgO/CaO mass ratio on the density and surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3)slags were investigated Results indicated that the density of slags decreased with the TiO_(2) content increasing from 20wt%to 30wt%,but it increased slightly with the MgO/CaO mass ratio increasing from 0.32 to 0.73.In view of silicate network structure,the density and the degree of polymerization(DOP)of network structure have a consistent trend.The addition of TiO_(2) reduced(Q^(3))^(2)/(Q^(2)) ratio(Q^(2) and Q^(3) represent structural unit with bridge oxygen number of 2 and 3,respectively)and then decreased DOP,which led to the decrease of slag density.The surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3) slags decreased dramatically with the TiO_(2) content increasing from 20wt%to 30wt%.Conversely,it increased with the MgO/CaO mass ratio increasing from 0.32 to 0.73.Furthermore,the iso-surface tension lines were obtained under 1723 K using the Tanaka developed model in view of Butler formula.It may be useful for slag optimization of ultra-high proportion(>80%)or even full vanadium titanomagnetite under BF smelting.
文摘Based on the coexistence theory of slag melt structure and Butler’s equation,a new calculation model has been proposed for the calculation of surface tension of slag melt.This model establishes a specific correlation between surface tension and mass action concentrations(activities) in the melt and on its surface on the basis of inner and surficial structures of slag melt.Calculated surface tensions of CaO-SiOand MnO-SiOslag melts are consistent with those measured.Furthermore,iso-surface tension lines of CaO-MnO-SiOslag melt have also been calculated.
基金Supported by the National Natural Science Foundation of China(21576168,21276163)
文摘The densities and surface tensions of [Bmim][TFO]/H2SO4, [Hmim][TFO]/H2SO4 and [Omim][TFO]/H2SO4 binary mixtures were measured by pycnometer and Wilhelmy plate method respectively. The results show that densities and surface tensions of the mixtures decreased monotonously with increasing temperatures and increasing ionic liquid （IL） molar fraction. IL with longer alkyl side-chain length brings a lower density and a smaller surface tension to the ILs/H2SO4 binary mixtures. The densities and surface tensions of the mixtures are fitted well by Jouyban-Acree （JAM） model and LWW model respectively. Redlich-Kister （R-K）equation and modified Redlich-Kister （R-K） equation describe the excess molar volumes and excess surface tensions of the mixtures well respectively. Adding a small amount of ILs （XIL 〈 0.1 ） into sulfuric acid brings an obvious decrease to the density and the surface tension. The results imply that the densities and surface tensions of IL5/H2SO4 binary mixtures can be modulated by changing the IL dosage or tailoring the IL structure.
文摘Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface tensions were calculated from crystallization induction times using classic homogeneous nucleation theory. Induction time and surface tension decreased at higher temperature.
基金Project(51206033)supported by the National Natural Science Foundation of ChinaProjects(2011M500652,2013T60354)supported by the China Postdoctoral Science FoundationProject(2011LBH-Z11139)supported by the Heilongjiang Postdoctoral Science Foundation,China
文摘In order to investigate the effect of additives and nano-particle on the surface tensions of lithium bromide(Li Br) aqueous solution/ammonia, many experiments were carried out based on Wilhelmy plate method. Firstly, the surface tension of Li Br aqueous solution with 1-octanol was measured and then the comparison between the measured results and previous experimental results was given to verify the measuring accuracy. Some new additives, such as cationic surfactants cetyltrimethyl ammonium chloride(CTAC), and cetyltrimethyl ammonium bromide(CTAB) were chosen in the experiments. The experimental results show that CTAC and CTAB can obviously reduce the surface tension of Li Br aqueous solution/ammonia. In addition, it is found that nano-particles cannot remarkably decrease the surface tension of Li Br aqueous solution/ammonia. However, the mixed addition of additives and nano-particles can remarkably affect the surface tension of Li Br aqueous solution/ammonia. That is to say, additives play more important role in reducing the surface tension of Li Br aqueous solution/ammonia. But nano-particles may enhance the heat transfer in the absorption refrigeration process.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50401013)the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University of China (NWPU) (Grant No. KP200903)
文摘Phase field investigation reveals that the stability of the planar interface is related to the anisotropic intensity of surface tension and the misorientation of preferred crystallographic orientation with respect to the heat flow direction. The large anisotropic intensity may compete to determine the stability of the planar interface. The destabilizing effect or the stabilizing effect depends on the misorientation. Moreover, the interface morphology of initial instability is also affected by the surface tension anisotropy.
文摘Surface tension of molten IF steel containing Ti and contact angle between the liquid steel and solid alumina were measured with sessile droplet method under Ar gas atmosphere at 1500, 1575 and 1600°C. The results show that titanium decreases the surface tension of the molten IF steel and the contact angle. The interfacial tension between the molten IF steel containing Ti and solid alumina decreases with increase in titanium content. The work of adhesion between molten IF steel containing Ti and solid alumina decreases slightly at 1550°C, but increases at 1600°C with increasing titanium content. It can be deduced that fine bubbles and fine alumina inclusions are easily entrapped in solidifying interface for IF steel containing Ti.
基金supported by the National Natural Science Foundation of China (No. 50972010)the Fundamental Research Funds for the Central Universities (No. FRF-TP-09-021B)the Austrian Science Foundation (No. P20488-N19)
文摘The surface tension of a promising lead-free solder Au-Bi-Sn alloys was investigated both by the sessile-drop method and calculation. Experimental measurements were carried out for two cross-sections with the constant gold to bismuth ration of 1:1 and 1:2. For all the investigated compositions, decrease of the surface tension is observed with increasing temperature. Meanwhile, the surface tension values were also calculated based on Butler’s equation, with using the newest research on thermodynamics data of Au-Bi-Sn ternary system. Compared with the experimental results, a good agreement was obtained.
基金Supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP)GTL Technology Development Consortium (Korean National Oil Corp., Korea Gas Corp., Daelim Industrial Co. and Hyundai Engineering Co.) under "Energy Efficiency & Resources Programs" of the Ministry of Knowledge Economy, Republic of Korea
文摘Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid circulation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid velocity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.
基金financial supports from the National Natural Science Foundation of China(Nos.51974022,U1738101)Fundamental Research Funds for the Central Universities,China(No.FRF-MP-20-17)。
文摘Surface roughness is an important factor that affects the wetting of molten metal on ceramics.The effect of surface roughness of the alumina substrate on the contact angle,contact diameter,drop height and surface tension of molten lead was investigated in the temperature range of 923-1123 K.The microstructure of the lead/substrate interface was observed by SEM.The surface free energy of alumina substrates was calculated by the geometrical average method.When the surface roughness of the substrate increased from 0.092 to 2.23μm,the surface free energy increased gradually,ranging from 13.356 to 39.998 mJ/m^(2).The contact diameter of lead droplets decreased from 9.111 to 7.19 mm.The lead drop height increased from 3.41 to 3.85 mm.The contact angle increased from 113.05°to 137.15°.Moreover,the surface depression of the alumina substrate was filled with lead,and no obvious change was observed.The results demonstrated that the wetting of lead drop on alumina substrates was consistent with the Wenzel state.
基金Projects(20775010,21075011) supported by the National Natural Science Foundation of ChinaProject(2008AA05Z405) supported by the National High Technology Research and Development Program of China+2 种基金Project(09JJ3016) supported by Hunan Provincial Natural Science Foundation,ChinaProject(09C066) supported by Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(2010CL01) supported by the Foundation of Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,China
文摘A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.
基金the National Natural Science Foundation of China (No. 50071009, 59674027)and the National Doctorate Fund of State Education Mi
文摘Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensions of liquid stable and undercooled Ni-Cu (x(Ni)=0.42) and Ni-Fe (x(Ni)=0.3 and 0.7) alloys are calculated using STCBE (Surface Tension Calculation based on Butler Equation) program. The agreement between calculated values and experimental data is good enough, and the temperature dependence of the surface tension can be reasonable down to 150-200 K under the liquid temperature of the alloys.
基金Supported by the National Natural Science Foundation of China （20776040 20876041 20736002） the National Basic Research Program of China （2009CB219902）+1 种基金 the Program for Changjiang Scholars and Innovative Research Team in University of China （Grant IRT0721） the 111 Project （Grant B08021） of China
文摘The equation of state(EOS)for square-well chain fluid with variable range(SWCF-VR) developed in our previous work based on statistical mechanical theory for chemical association is employed for the correlations of surface tension and viscosity of common fluids and ionic liquids(ILs).A model of surface tension for multi-component mixtures is presented by combining the SWCF-VR EOS and the scaled particle theory and used to produce the surface tension of binary and ternary mixtures.The predicted surface tensions are in excellent agreement with the experimental data with an overall average absolute relative deviation(AAD)of 0.36%.A method for the calculation of dynamic viscosity of common fluids and ILs at high pressure is presented by combining Eyring’s rate theory of viscosity and the SWCF-VR EOS.The calculated viscosities are in good agreement with the experimental data with the overall AAD of 1.44% for 14 fluids in 84 cases.The salient feature is that the molecular parameters used in these models are self-consistent and can be applied to calculate different thermodynamic properties such as pVT,vapor-liquid equilibrium,caloric properties,surface tension,and viscosity.
文摘In molten phase metallurgical processes,mixing via gas injection has a vital role in obtaining a homogeneous product.The efficiency of mixing depends on operational variables such as gas flow rate and slag height as well as physical properties of the molten phases.A numerical simulation is conducted to study the above parameters in the flow behavior of a bottom-blown bath.The molten metal and the slag are modeled by water and oil,respectively.The numerical results,particularly the mixing time,are validated against experimental data.The results show that mixing time increases as the slag height increases and decreases as the density of the slag material increases.The mixing time decreases with an increase in the density of the primary phase;however,it increases as the surface tension between air and water increases.A case with properties close to a real molten metal is also modeled.The performance of the system is influenced by the momentum rather than the dissipative forces.Thus,the effect of the density of the molten phase on the mixing process is more pronounced compared to the effect of the surface tension between the air and the molten phase.
基金the Scientific Research Foundation of the State Education Ministry for Returned Overseas Chinese Scholar.
文摘A new equation for predicting surface tension is proposed based on the thermodynamic definition of surface tension and the expression of the Gibbs free energy of the system. Using the NRTL equation to represent the excess Gibbs free energy, a two-parameter surface tension equation is derived. The feasibility of the new equation has been tested in terms of 124 binary and 16 multicomponent systems(13-ternary and 3-quaternary) with absolute relative deviations of 0.59% and 1.55% respectively. This model is also predictive for the temperature dependence of surface tension of liquid mixtures. It is shown that, with good accuracy, this equation is simple and reliable for practical use.
文摘Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.
文摘A setup for recording surface tension curves at a mercury drop during potential scanning is designed based on photo-sensitive detection system. Surface tension spectrum at Hg drop can be recorded by voltam0metdc study. A Yb（Ⅲ）-NO2 catalytic reduction system was used for characterization. The simple, sensitive technique can be expected to provide fresh information on molecular interactions at electrode surfaces.
