Experimental data are presented for the void fraction and the shear stresses of stratified gas-liquid flow in a pipe. A new technique was used to measure the interface shear stress. The interfacial shear stress was de...Experimental data are presented for the void fraction and the shear stresses of stratified gas-liquid flow in a pipe. A new technique was used to measure the interface shear stress. The interfacial shear stress was determined by using two methods: a momentum balance of gas and an extrapolation of the Reynolds shear stress profile at the gas-liquid interface. A new formula , relating to the interfacial friction factor with the void fraction and superficial gas Reynold number, was developed to predict the interface shear stress . The predicted values are in good agreement with experimental data.展开更多
At room temperature, the rolling treatment of steel-mushy Al-7graphite bonding plate was carried out under different relative reduction. The influence of rolling on interfacial mechanical property of this bonding plat...At room temperature, the rolling treatment of steel-mushy Al-7graphite bonding plate was carried out under different relative reduction. The influence of rolling on interfacial mechanical property of this bonding plate was studied. The results show that, for steel-mushy Al-7graphite bonding plate which is made up of 1.2 mm in thickness 08AI steel plate and 2.0 mm in thickness Al-7graphite layer, there is a nonlinear relationship between interfacial shear strength of bonding plate and relative reduction of rolling. When relative reduction of rolling is smaller than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate increases gradually. When relative reduction of rolling is bigger than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate decreases continuously. When relative reduction of rolling is 2.59%, the largest interfacial shear strength 77.0 MPa can be obtained.展开更多
Heterocyclic aramid fibers,a typical kind of high-performance fibers,have been widely used in aerospace and protection fields because of their excellent mechanical properties.However,the application of heterocyclic ar...Heterocyclic aramid fibers,a typical kind of high-performance fibers,have been widely used in aerospace and protection fields because of their excellent mechanical properties.However,the application of heterocyclic aramid fibers as a reinforcement is hindered by the weak interfacial combination with matrix materials,especially epoxy.Traditional strategies enhancing the interfacial shear strength(IFSS)usually decrease the tensile strength.Therefore,simultaneous enhancement of both mechanical properties remains a challenge.Herein,we report a novel heterocyclic aramid fiber with high interfacial shear strength(49.3 MPa)and tensile strength(6.27 GPa),in which 4,4′-diamino-2′-chlorobenzanilide(DABA-Cl)and a small amount of graphene oxide(GO)are introduced through in-situ polymerization.Hydrogen bonds andπ–πinteraction between GO and polymer chains trigger the enhancement in crystallinity,orientation,and lateral interaction of the fibers,thus improving the tensile strength and interfacial shear strength of the fibers.Moreover,the interfacial interaction between fiber and epoxy is enhanced due to the improvement of the surface polarity of the fibers caused by DABA-Cl.Therefore,a method to improve both tensile strength and interfacial shear strength of heterocyclic aramid fibers was found by introducing GO and DABA-Cl,which may provide guidance for the design and preparation of other high-performance fibers.展开更多
Statically push-out tests of 20 steel reinforced concrete short columns （SRCSC） with stud connectors on the surface of shape steel after fire and two SRCSC under ambient temperature were carried out, in order to stu...Statically push-out tests of 20 steel reinforced concrete short columns （SRCSC） with stud connectors on the surface of shape steel after fire and two SRCSC under ambient temperature were carried out, in order to study the failure mode, load-slip relationship and the interfacial shear transfer of SRC members after fire. Experimental results show that the typical failure modes and load-slip curves of SRCSC after fire are almost the same as the case under ambient temperature. The interfacial shear transfer of SRCSC declines exponentially not only with the increase of the peak temperature the specimen experienced but also with the increase of the peak temperature duration. The interfacial shear transfer of the specimens with studs arranged at the steel web is much higher than those with studs arranged at the steel flange. Empirical formulas of SRCSC interfacial shear transfer after fire are proposed, and the calculated results generally agree well with the experimental results.展开更多
The oil/water interfacial properties of crude oil emulsions formed by alkaline/surfactant/ polymer（ASP） flooding in the Daqing Oilfield were investigated in this paper by the measurement of interfacial tension,inter...The oil/water interfacial properties of crude oil emulsions formed by alkaline/surfactant/ polymer（ASP） flooding in the Daqing Oilfield were investigated in this paper by the measurement of interfacial tension,interfacial shear viscosity and Zeta potential of the oil/water system.The result showed that both NaOH and Na_2CO_3 could react with acid substances in the crude oil to produce interfacially active components,which are adsorbed on the interfaces between the aqueous phase and oil phase, resulting in a decrease of the interfacial tension,negatively charging the surface of oil droplets,but making little change in the interfacial shear viscosity.For the same ionic strength of NaOH and Na_2CO_3, the interfacial tension of NaOH solution-crude oil system is lower,but the interfacial shear viscosity of NaOH solution-crude oil system is higher,than that of Na_2CO_3 solution-crude oil system.The negative value of the Zeta potential on the surface of the oil droplets is large.Accordingly,the O/W emulsion of NaOH solution-crude oil system is more stable than that of Na_2CO_3 solution-crude oil system.展开更多
The bolt anchoring force is closely related to the shear properties of the anchor interface. The shear stress distribution of full-length grouted bolts is analyzed based on the stress-strain relationship among the bol...The bolt anchoring force is closely related to the shear properties of the anchor interface. The shear stress distribution of full-length grouted bolts is analyzed based on the stress-strain relationship among the bolt, grout, rock mass and bond interface,considering the shear properties of the grout and contact interface bonding behavior. In this case, the interfacial shear stress of the grout and rock mass and the bolt axial force are obtained under pull-out and normal working conditions. The results show that the peak shear stress of the interface with the shear deformation of the bond interface is significantly lower than that without it when the pull-out force is applied. When designing bolt parameters of grade IV and V rock mass, the relative deformation between the rock mass and anchor should be considered, with a “unimodal” to “bimodal” shear stress distribution.In the case of a low elastic modulus of rock masses,both the shear stress concentration and distribution range are obvious, and the neutral point is near the bolt head. As the elastic modulus increases, the shear stress concentration and distribution range are reduced, and the neutral point moves towards the distal end. As a result, the optimum length of fulllength grouted bolts can be determined by in-situ pull-out tests and decreases with the increased elastic modulus of the rock mass.展开更多
The influence of petroleum sulphonate (TRS) on interfacial properties and stability of the emulsions formed by formation water and asphaltene, resin and crude model oils from Gudong crude oil was investigated by measu...The influence of petroleum sulphonate (TRS) on interfacial properties and stability of the emulsions formed by formation water and asphaltene, resin and crude model oils from Gudong crude oil was investigated by measurement of interfacial shear viscosity, interfacial tension (IFT) and emulsion stability. With increasing petroleum sulphonate concentration, IFT between the formation water and the asphaltene, resin and crude model oils decreases significantly. The interfacial shear viscosity and emulsion stability of asphaltene and crude model oil system increase for the petroleum sulphonate concentration in the range 0.1% to 0.3%, and decrease slightly when the concentration of the surfactant is 0.5%. There exists a close correlation between the interfacial shear viscosity and the stability of the emulsions formed by asphaltene or crude model oils and petroleum sulphonate solution.The stability of the emulsions is determined by the strength of the interfacial film formed of petroleum sulphonate molecules and the natural interfacial active components in the asphaltene fraction and the crude oil. The asphaltene in the crude oil plays a major role in determining the interfacial properties and the stability of the emulsions.展开更多
The interfacial properties of steel-mushy Al-28Pb bonding plate with different interfacial structures, and the influence of ratio of Fe-Al compound at the interface on interfacial shear strength were investigated. The...The interfacial properties of steel-mushy Al-28Pb bonding plate with different interfacial structures, and the influence of ratio of Fe-Al compound at the interface on interfacial shear strength were investigated. The results show that there is a nonlinear relationship between the ratio of Fe-Al compound at the interface and the interfacial shear strength. When the ratio of Fe-Al compound at the interface is smaller than 71.4%, with the increase of the ratio of Fe-Al compound at the interface, the interfacial shear strength increases gradually; when the ratio of Fe-Al compound at the interface is larger than 71.4%, with the increase of the ratio of Fe-Al compound at the interface, the interfacial shear strength decreases continuously; when the ratio of Fe-Al compound at the interface is 71.4%, the largest interfacial shear strength 70.2MPa is obtained.展开更多
Single-fiber pull-out testing (SFPOT) methods are frequently used to evaluate the interfacial adhesion between fiber and matrix in composite materials. To make such pull-out measurements, however, the length of embedd...Single-fiber pull-out testing (SFPOT) methods are frequently used to evaluate the interfacial adhesion between fiber and matrix in composite materials. To make such pull-out measurements, however, the length of embedded fiber must be small enough so that the fiber does not break before it is pulled freely. This is difficult to achieve by conventional methods with fibers of small diameter, such as the carbon fibers. In this paper, a fiber pull-out experiment is described. Specialized apparatus in our laboratory, as well as this technique for sample preparation are discussed in detail. The interfacial shear strength of carbon fiber/resin matrix composites is analyzed quantitatively by using the finite-element method. The SFPOT system has been proved to be an available means for the study of interfacial properties for carbon fiber/resin matrix composites.展开更多
The bonding of a steel plate to Al-20Sn slurry was conducted using thecasting rolling technique. The surface of the steel plate was defatted, descaled, immersed (inK_2ZrF_6 flux aqueous solution) and stoved. Al-20Sn s...The bonding of a steel plate to Al-20Sn slurry was conducted using thecasting rolling technique. The surface of the steel plate was defatted, descaled, immersed (inK_2ZrF_6 flux aqueous solution) and stoved. Al-20Sn slurry was prepared using the electromagneticmechanical starring method. The interfacial mechanical property of the bonding plate was researchedto determine the relationship between the diffusion time and the interfacial shear strength. Inorder to identify the mechanism of bonding, the interfacial structure of the bonding plate wasstudied. The results show that at a prebeat temperature of the steel plate of 505 deg C and a solidfraction of Al-20Sn slurry of 35 percent, the relationship between the interfacial shear strength Sand the diffusion time t is S=28.8+4.3t-0.134t^2 +0.0011t^3. When the diffusion time is 22 s, thelargest interfacial shear strength is 70.3 MPa, and the corresponding interface is a new one whichis made up of Fe-Al compound and Fe-Al solid solution alternatively and in a right proportion. Inthis interfacial structure, the interfacial embrittlement does not happen and Fe-Al compound canplay its role in strong combination adequately.展开更多
Thailand has a huge variability of bast fiber plants,some of which have been little researched regarding their applicability in composites.Bast fiber(bundle)s from different species were investigated and incorporated ...Thailand has a huge variability of bast fiber plants,some of which have been little researched regarding their applicability in composites.Bast fiber(bundle)s from different species were investigated and incorporated into a polylactide(PLA)matrix by injection molding.Hemp and kenaf were used as well-studied fibers,while roselle,Fryxell and paper mulberry are less extensively characterized.Tensile strength,tensile modulus and interfacial shear strength(IFSS)of single fiber(bundle)s were highest for hemp,followed by kenaf,roselle,Fryxell and paper mulberry.Despite the lower tensile strength and IFSS of paper mulberry,the highest tensile strength was achieved for the paper mulberry/PLA composite followed by hemp/PLA.Scanning electron microscope(SEM)analyses showed that the single cells in paper mulberry fiber bundles,in contrast to the other fiber types investigated,were only partially bonded to each other,which explains the lower strength of the fiber bundles.The higher aspect ratio of fiber(bundle)s of paper mulberry in the PLA composite can explain the good composite characteristics.Apart from hemp,paper mulberry shows the best reinforcing effect in the PLA matrix and offers interesting potential for composite applications.Compared to neat PLA,the tensile strength could be increased by 24%and the tensile modulus by 54%.展开更多
Vertically orientated TiO2 nanotube array with diameters ranging from 60 up to 80 nm and length of 4 μm was grown on titanium by anodization.Crack initiation,propagation and saturation were studied using the substrat...Vertically orientated TiO2 nanotube array with diameters ranging from 60 up to 80 nm and length of 4 μm was grown on titanium by anodization.Crack initiation,propagation and saturation were studied using the substrate straining test.The results show that annealing obviously modifies the interfaces.With the increase of tensile strain,cracks in TiO2 nanotube films propagate rapidly and reach the saturation within a narrow strain gap.Interfacial shear strengths of TiO2 nanotube films without annealing,with 250 ℃ annealing and with 400 ℃ annealing can be estimated as 163.3,370.2 and 684.5 MPa,respectively.The critical energy release rates of TiO2 nanotube films are calculated as 49.6,102.6 and 392.7 J/m2,respectively.The fracture toughnesses of TiO2 nanotube films are estimated as 0.996,1.433 and 2.803 MPa-m1/2,respectively.The interfacial bonding mechanism of TiO2 nanotube film is chemical bonding.展开更多
Curvature method was used to measure the residual stress and substrate straining tensile test was carried out to study the debonding behavior of TiO2 nanotube film. The results indicate that the internal residual stre...Curvature method was used to measure the residual stress and substrate straining tensile test was carried out to study the debonding behavior of TiO2 nanotube film. The results indicate that the internal residual stress is -54 MPa. The strains of debonding initiation of TiO2 nanotube films without annealing, with 250 °C annealing and with 400 °C annealing are 2.6%, 5.1% and 8.6%, respectively, and the average radii of the debonding patches with debonding initiation are 27.5, 17.1 and 19.4 μm, respectively. The true critical debonding stresses of TiO2 nanotube films without annealing, with 250 °C annealing and with 400 °C annealing can be estimated as 220.4, 394.5 and 627.9 MPa, respectively. Interfacial shear lag model is modified and polynomial fitting equation of the interfacial shear strength of TiO2 nanotube film is demonstrated under debonding conditions. The modification and polynomial fitting are reliable since good agreement of the interfacial shear strengths after fitting is obtained compared with those results from the crack density analysis.展开更多
The interfacial status of the steel-aluminum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and...The interfacial status of the steel-aluminum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and X-ray diffraction . The results showed that the layer of flux (the minimum thickness was 15 μm on the steel plate surface) could protect the steel plate surface from oxidizing effectively at high temperature in solid to liquid bonding. The melt temperatUre of the flux should be lower than 580 ℃ so that it could be melted and removed completely. No. 1 flux (patent product made by the author) made up of halogeindes could also force liquid aluminum to infiltrate into steel plate surface and thus the interfacial shear strength of the bonding plate was rather large.展开更多
In this work,polyethylene terephthalate(PET) fibers were continuously treated by atmospheric dielectric barrier discharge(DBD) in Ar mixed O2 plasma,and the discharge was characterized by electrical function and optic...In this work,polyethylene terephthalate(PET) fibers were continuously treated by atmospheric dielectric barrier discharge(DBD) in Ar mixed O2 plasma,and the discharge was characterized by electrical function and optical diagnostics.It is found that the interfacial adhesion strength between treated PET fiber and resorcinol formaldehyde latex(RFL)(little)-rubber was improved(about 50%) by the measurement of interfacial shear strength(IFSS) and peel test.The wettability was improved rapidly in the initial treatment time.It is considered that oxidation chemical reaction as the major role of PET fiber surface modification is ahead of the physical etching effect.The high density of atomic oxygen in the plasma by optical emission spectroscopy supports the purpose.According to the scanning electron micrograph(SEM) image in the work,the longer treatment time obviously caused physical etching effect,which shall be less responsible for the improvement of the wettability.展开更多
The segregated flow pattern, which occurs in a 26.1 mm diameter, horizontal, stainless steel test section, is investigated. Pressure gradient and in situ phase distribution data were obtained for different combination...The segregated flow pattern, which occurs in a 26.1 mm diameter, horizontal, stainless steel test section, is investigated. Pressure gradient and in situ phase distribution data were obtained for different combinations of phase superficial velocities ranging from 0.05 m.s^-1 to 0,96 m.s^-1. For the current small Eoetvoes number liquid-liquid system （EOD=4.77）, the dominant effect of interfacial tension and wall-wetting properties of the liquids over the gravity is considered. The approach introduces the closure relationship for the case of turbulent flow m a rough pipe, and attempts to modify the two-fluid model to account for the curved interface. In present flow rates range, wave amplitudes were found small, while interfacial mixing was observed. An adjustable definition for hydraulic diame- ters of two fluids and interfacial friction factor is adopted. The predicted pressure gradient and in situ phase distribution data have been compared with present experimental data and those reported in the literature.展开更多
To study the bridging effect of partly-cured Z-pin,Z-pins with different curing degrees are manufactured by controlling pultrusion parameters.A unit cell is selected to analyze the stress of Z-pinned laminates and the...To study the bridging effect of partly-cured Z-pin,Z-pins with different curing degrees are manufactured by controlling pultrusion parameters.A unit cell is selected to analyze the stress of Z-pinned laminates and the quantitative relationship between the maximum bridging force and Z-pin diameter,embedded length,interfacial shear strength and tensile strength is acquired.The Z-pin″bridging law″test and Z-pin tensile test are carried out to study the effect of Z-pin′s curing degree on bridging effect,and the bridging efficiency is defined to evaluate the reinforcement effect of Z-pin.The modeⅠinterlaminar fracture toughness(G_(ⅠC))is measured by the double cantilever beam test.The experimental results show that Z-pin′s co-curing with laminate matrix can improve the bridging force significantly and the fitting results show a linear relationship between Z-pin curing degree and interfacial shear strength.The three-dimensional images of the surface of pullout Z-pins indicate that the failure mode changed from totally interfacial debonding to a mixed mode.Finally,the reinforcement by partly-cured Z-pin can be used to further enhance the interlaminar toughness.Compared with completely-cured Z-pin,G_(ⅠC) of Z-pin with 67.6% curing degree increases by 47.0%.展开更多
The bonding of solid steel to liquid aluminum was conducted using rapidsolidification. The influence of diffusion time on interfacial shear strength was studied. Theresults show that when the temperature of aluminum l...The bonding of solid steel to liquid aluminum was conducted using rapidsolidification. The influence of diffusion time on interfacial shear strength was studied. Theresults show that when the temperature of aluminum liquid is 700℃ and the preheat temperature ofsteel plate is 250℃, the relationship between diffusion time (t) and interfacial shear strength(σ) is σ =15.1+8.14t-037t^2 +0.005t^3, and the maximum interfacial shear strength is 71.1 MPa.展开更多
The bonding of solid steel plate to liquid Al was conducted using rapid solidification. The influence of thickness of Fe-Al compound layer at the interface on interfacial shear strength of bonding plate was studied. T...The bonding of solid steel plate to liquid Al was conducted using rapid solidification. The influence of thickness of Fe-Al compound layer at the interface on interfacial shear strength of bonding plate was studied. The results show that the relationship between thickness of Fe-AI compound layer and interfacial shear strength is 5=30.4+8.51 h-0.51 h2 +0.007 h3 (where h is thickness of Fe-AI compound layer, S is interfacial shear strength). When thickness of Fe-AI compound layer is 10.7 um, the largest interfacial shear strength is 71.6 MPa.展开更多
Current methodologies used for the inference of thin film stress through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate...Current methodologies used for the inference of thin film stress through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. By considering a circular thin film/substrate system subject to non-uniform, but axisymmetric misfit strain distributions in the thin film, we derived relations between the film stresses and the misfit strain, and between the plate system＇s curvatures and the misfit strain. These relations feature a “local” part which involves a direct dependence of the stress or curvature components on the misfit strain at the same point, and a “non-local” part which reflects the effect of misfit strain of other points on the location of scrutiny. Most notably, we also derived relations between the polar components of the film stress and those of system curvatures which allow for the experimental inference of such stresses from full-field curvature measurements in the presence of arbitrary radial non-uniformities. These relations also feature a “non-local” dependence on curvatures making a full-field measurement a necessity. Finally, it is shown that the interfacial shear tractions between the film and the substrate are proportional to the radial gradients of the first curvature invariant and can also be inferred experimentally.展开更多
基金Supported by the National Natural Science Foundation of China(No.59236130).
文摘Experimental data are presented for the void fraction and the shear stresses of stratified gas-liquid flow in a pipe. A new technique was used to measure the interface shear stress. The interfacial shear stress was determined by using two methods: a momentum balance of gas and an extrapolation of the Reynolds shear stress profile at the gas-liquid interface. A new formula , relating to the interfacial friction factor with the void fraction and superficial gas Reynold number, was developed to predict the interface shear stress . The predicted values are in good agreement with experimental data.
文摘At room temperature, the rolling treatment of steel-mushy Al-7graphite bonding plate was carried out under different relative reduction. The influence of rolling on interfacial mechanical property of this bonding plate was studied. The results show that, for steel-mushy Al-7graphite bonding plate which is made up of 1.2 mm in thickness 08AI steel plate and 2.0 mm in thickness Al-7graphite layer, there is a nonlinear relationship between interfacial shear strength of bonding plate and relative reduction of rolling. When relative reduction of rolling is smaller than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate increases gradually. When relative reduction of rolling is bigger than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate decreases continuously. When relative reduction of rolling is 2.59%, the largest interfacial shear strength 77.0 MPa can be obtained.
基金the Ministry of Science and Technology of China(No.2016YFA0200100)the Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXTD-202001)+1 种基金the National Natural Science Foundation of China(Nos.52102035,52021006,T2188101,51720105003,and 21790052)the Strategic Priority Research Program of CAS(No.XDB36030100).
文摘Heterocyclic aramid fibers,a typical kind of high-performance fibers,have been widely used in aerospace and protection fields because of their excellent mechanical properties.However,the application of heterocyclic aramid fibers as a reinforcement is hindered by the weak interfacial combination with matrix materials,especially epoxy.Traditional strategies enhancing the interfacial shear strength(IFSS)usually decrease the tensile strength.Therefore,simultaneous enhancement of both mechanical properties remains a challenge.Herein,we report a novel heterocyclic aramid fiber with high interfacial shear strength(49.3 MPa)and tensile strength(6.27 GPa),in which 4,4′-diamino-2′-chlorobenzanilide(DABA-Cl)and a small amount of graphene oxide(GO)are introduced through in-situ polymerization.Hydrogen bonds andπ–πinteraction between GO and polymer chains trigger the enhancement in crystallinity,orientation,and lateral interaction of the fibers,thus improving the tensile strength and interfacial shear strength of the fibers.Moreover,the interfacial interaction between fiber and epoxy is enhanced due to the improvement of the surface polarity of the fibers caused by DABA-Cl.Therefore,a method to improve both tensile strength and interfacial shear strength of heterocyclic aramid fibers was found by introducing GO and DABA-Cl,which may provide guidance for the design and preparation of other high-performance fibers.
基金Acknowledgements This research is supported by the National Science Foundation of China （Grant Nos. 50908118 and No. 51308307）, Ningbo Science Foundation （No. 2013A610194） and Ningbo Key Scientific Projects （No. XKL11D2079）.
文摘Statically push-out tests of 20 steel reinforced concrete short columns （SRCSC） with stud connectors on the surface of shape steel after fire and two SRCSC under ambient temperature were carried out, in order to study the failure mode, load-slip relationship and the interfacial shear transfer of SRC members after fire. Experimental results show that the typical failure modes and load-slip curves of SRCSC after fire are almost the same as the case under ambient temperature. The interfacial shear transfer of SRCSC declines exponentially not only with the increase of the peak temperature the specimen experienced but also with the increase of the peak temperature duration. The interfacial shear transfer of the specimens with studs arranged at the steel web is much higher than those with studs arranged at the steel flange. Empirical formulas of SRCSC interfacial shear transfer after fire are proposed, and the calculated results generally agree well with the experimental results.
基金supported by the National Basic Research Program of China (973 Program) (Grant No.2006CB705805)the National Key Scientific and Technological Project (863 Project)(Grant No.2008ZX05011)
文摘The oil/water interfacial properties of crude oil emulsions formed by alkaline/surfactant/ polymer（ASP） flooding in the Daqing Oilfield were investigated in this paper by the measurement of interfacial tension,interfacial shear viscosity and Zeta potential of the oil/water system.The result showed that both NaOH and Na_2CO_3 could react with acid substances in the crude oil to produce interfacially active components,which are adsorbed on the interfaces between the aqueous phase and oil phase, resulting in a decrease of the interfacial tension,negatively charging the surface of oil droplets,but making little change in the interfacial shear viscosity.For the same ionic strength of NaOH and Na_2CO_3, the interfacial tension of NaOH solution-crude oil system is lower,but the interfacial shear viscosity of NaOH solution-crude oil system is higher,than that of Na_2CO_3 solution-crude oil system.The negative value of the Zeta potential on the surface of the oil droplets is large.Accordingly,the O/W emulsion of NaOH solution-crude oil system is more stable than that of Na_2CO_3 solution-crude oil system.
基金funded by the Natural Science Foundation of China(Grants Nos.52179113,42207199,41831278)。
文摘The bolt anchoring force is closely related to the shear properties of the anchor interface. The shear stress distribution of full-length grouted bolts is analyzed based on the stress-strain relationship among the bolt, grout, rock mass and bond interface,considering the shear properties of the grout and contact interface bonding behavior. In this case, the interfacial shear stress of the grout and rock mass and the bolt axial force are obtained under pull-out and normal working conditions. The results show that the peak shear stress of the interface with the shear deformation of the bond interface is significantly lower than that without it when the pull-out force is applied. When designing bolt parameters of grade IV and V rock mass, the relative deformation between the rock mass and anchor should be considered, with a “unimodal” to “bimodal” shear stress distribution.In the case of a low elastic modulus of rock masses,both the shear stress concentration and distribution range are obvious, and the neutral point is near the bolt head. As the elastic modulus increases, the shear stress concentration and distribution range are reduced, and the neutral point moves towards the distal end. As a result, the optimum length of fulllength grouted bolts can be determined by in-situ pull-out tests and decreases with the increased elastic modulus of the rock mass.
基金国家重点基础研究发展计划(973计划)，an International Cooperation Research Program
文摘The influence of petroleum sulphonate (TRS) on interfacial properties and stability of the emulsions formed by formation water and asphaltene, resin and crude model oils from Gudong crude oil was investigated by measurement of interfacial shear viscosity, interfacial tension (IFT) and emulsion stability. With increasing petroleum sulphonate concentration, IFT between the formation water and the asphaltene, resin and crude model oils decreases significantly. The interfacial shear viscosity and emulsion stability of asphaltene and crude model oil system increase for the petroleum sulphonate concentration in the range 0.1% to 0.3%, and decrease slightly when the concentration of the surfactant is 0.5%. There exists a close correlation between the interfacial shear viscosity and the stability of the emulsions formed by asphaltene or crude model oils and petroleum sulphonate solution.The stability of the emulsions is determined by the strength of the interfacial film formed of petroleum sulphonate molecules and the natural interfacial active components in the asphaltene fraction and the crude oil. The asphaltene in the crude oil plays a major role in determining the interfacial properties and the stability of the emulsions.
文摘The interfacial properties of steel-mushy Al-28Pb bonding plate with different interfacial structures, and the influence of ratio of Fe-Al compound at the interface on interfacial shear strength were investigated. The results show that there is a nonlinear relationship between the ratio of Fe-Al compound at the interface and the interfacial shear strength. When the ratio of Fe-Al compound at the interface is smaller than 71.4%, with the increase of the ratio of Fe-Al compound at the interface, the interfacial shear strength increases gradually; when the ratio of Fe-Al compound at the interface is larger than 71.4%, with the increase of the ratio of Fe-Al compound at the interface, the interfacial shear strength decreases continuously; when the ratio of Fe-Al compound at the interface is 71.4%, the largest interfacial shear strength 70.2MPa is obtained.
基金the High Technology Research and Development Programme of China.
文摘Single-fiber pull-out testing (SFPOT) methods are frequently used to evaluate the interfacial adhesion between fiber and matrix in composite materials. To make such pull-out measurements, however, the length of embedded fiber must be small enough so that the fiber does not break before it is pulled freely. This is difficult to achieve by conventional methods with fibers of small diameter, such as the carbon fibers. In this paper, a fiber pull-out experiment is described. Specialized apparatus in our laboratory, as well as this technique for sample preparation are discussed in detail. The interfacial shear strength of carbon fiber/resin matrix composites is analyzed quantitatively by using the finite-element method. The SFPOT system has been proved to be an available means for the study of interfacial properties for carbon fiber/resin matrix composites.
基金This work was supported by the National Natural Science Foundation of China (No.50274047)Beijing Jiaotong University Foundation
文摘The bonding of a steel plate to Al-20Sn slurry was conducted using thecasting rolling technique. The surface of the steel plate was defatted, descaled, immersed (inK_2ZrF_6 flux aqueous solution) and stoved. Al-20Sn slurry was prepared using the electromagneticmechanical starring method. The interfacial mechanical property of the bonding plate was researchedto determine the relationship between the diffusion time and the interfacial shear strength. Inorder to identify the mechanism of bonding, the interfacial structure of the bonding plate wasstudied. The results show that at a prebeat temperature of the steel plate of 505 deg C and a solidfraction of Al-20Sn slurry of 35 percent, the relationship between the interfacial shear strength Sand the diffusion time t is S=28.8+4.3t-0.134t^2 +0.0011t^3. When the diffusion time is 22 s, thelargest interfacial shear strength is 70.3 MPa, and the corresponding interface is a new one whichis made up of Fe-Al compound and Fe-Al solid solution alternatively and in a right proportion. Inthis interfacial structure, the interfacial embrittlement does not happen and Fe-Al compound canplay its role in strong combination adequately.
基金The present work was funded within the framework of the BMBF Exchange Project“Thai-German Agro-Based Fiber Exchange Programme-Sustainable Development:From Plant to Product(Acronym:AgroFiber)”under Registration No.01DP15016.
文摘Thailand has a huge variability of bast fiber plants,some of which have been little researched regarding their applicability in composites.Bast fiber(bundle)s from different species were investigated and incorporated into a polylactide(PLA)matrix by injection molding.Hemp and kenaf were used as well-studied fibers,while roselle,Fryxell and paper mulberry are less extensively characterized.Tensile strength,tensile modulus and interfacial shear strength(IFSS)of single fiber(bundle)s were highest for hemp,followed by kenaf,roselle,Fryxell and paper mulberry.Despite the lower tensile strength and IFSS of paper mulberry,the highest tensile strength was achieved for the paper mulberry/PLA composite followed by hemp/PLA.Scanning electron microscope(SEM)analyses showed that the single cells in paper mulberry fiber bundles,in contrast to the other fiber types investigated,were only partially bonded to each other,which explains the lower strength of the fiber bundles.The higher aspect ratio of fiber(bundle)s of paper mulberry in the PLA composite can explain the good composite characteristics.Apart from hemp,paper mulberry shows the best reinforcing effect in the PLA matrix and offers interesting potential for composite applications.Compared to neat PLA,the tensile strength could be increased by 24%and the tensile modulus by 54%.
基金Project(50604017) supported by the National Natural Science Foundation of ChinaProject(20110946Z) supported by the State Key Laboratory of Powder Metallurgy,China
文摘Vertically orientated TiO2 nanotube array with diameters ranging from 60 up to 80 nm and length of 4 μm was grown on titanium by anodization.Crack initiation,propagation and saturation were studied using the substrate straining test.The results show that annealing obviously modifies the interfaces.With the increase of tensile strain,cracks in TiO2 nanotube films propagate rapidly and reach the saturation within a narrow strain gap.Interfacial shear strengths of TiO2 nanotube films without annealing,with 250 ℃ annealing and with 400 ℃ annealing can be estimated as 163.3,370.2 and 684.5 MPa,respectively.The critical energy release rates of TiO2 nanotube films are calculated as 49.6,102.6 and 392.7 J/m2,respectively.The fracture toughnesses of TiO2 nanotube films are estimated as 0.996,1.433 and 2.803 MPa-m1/2,respectively.The interfacial bonding mechanism of TiO2 nanotube film is chemical bonding.
基金Project (51274248) supported by the National Natural Science Foundation of ChinaProject (20110946Z) supported by the State Key Laboratory of Powder Metallurgy, China
文摘Curvature method was used to measure the residual stress and substrate straining tensile test was carried out to study the debonding behavior of TiO2 nanotube film. The results indicate that the internal residual stress is -54 MPa. The strains of debonding initiation of TiO2 nanotube films without annealing, with 250 °C annealing and with 400 °C annealing are 2.6%, 5.1% and 8.6%, respectively, and the average radii of the debonding patches with debonding initiation are 27.5, 17.1 and 19.4 μm, respectively. The true critical debonding stresses of TiO2 nanotube films without annealing, with 250 °C annealing and with 400 °C annealing can be estimated as 220.4, 394.5 and 627.9 MPa, respectively. Interfacial shear lag model is modified and polynomial fitting equation of the interfacial shear strength of TiO2 nanotube film is demonstrated under debonding conditions. The modification and polynomial fitting are reliable since good agreement of the interfacial shear strengths after fitting is obtained compared with those results from the crack density analysis.
文摘The interfacial status of the steel-aluminum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and X-ray diffraction . The results showed that the layer of flux (the minimum thickness was 15 μm on the steel plate surface) could protect the steel plate surface from oxidizing effectively at high temperature in solid to liquid bonding. The melt temperatUre of the flux should be lower than 580 ℃ so that it could be melted and removed completely. No. 1 flux (patent product made by the author) made up of halogeindes could also force liquid aluminum to infiltrate into steel plate surface and thus the interfacial shear strength of the bonding plate was rather large.
文摘In this work,polyethylene terephthalate(PET) fibers were continuously treated by atmospheric dielectric barrier discharge(DBD) in Ar mixed O2 plasma,and the discharge was characterized by electrical function and optical diagnostics.It is found that the interfacial adhesion strength between treated PET fiber and resorcinol formaldehyde latex(RFL)(little)-rubber was improved(about 50%) by the measurement of interfacial shear strength(IFSS) and peel test.The wettability was improved rapidly in the initial treatment time.It is considered that oxidation chemical reaction as the major role of PET fiber surface modification is ahead of the physical etching effect.The high density of atomic oxygen in the plasma by optical emission spectroscopy supports the purpose.According to the scanning electron micrograph(SEM) image in the work,the longer treatment time obviously caused physical etching effect,which shall be less responsible for the improvement of the wettability.
基金the National High Technology Research and Development Program of China (2006AA09Z333)
文摘The segregated flow pattern, which occurs in a 26.1 mm diameter, horizontal, stainless steel test section, is investigated. Pressure gradient and in situ phase distribution data were obtained for different combinations of phase superficial velocities ranging from 0.05 m.s^-1 to 0,96 m.s^-1. For the current small Eoetvoes number liquid-liquid system （EOD=4.77）, the dominant effect of interfacial tension and wall-wetting properties of the liquids over the gravity is considered. The approach introduces the closure relationship for the case of turbulent flow m a rough pipe, and attempts to modify the two-fluid model to account for the curved interface. In present flow rates range, wave amplitudes were found small, while interfacial mixing was observed. An adjustable definition for hydraulic diame- ters of two fluids and interfacial friction factor is adopted. The predicted pressure gradient and in situ phase distribution data have been compared with present experimental data and those reported in the literature.
基金financially supported by the Aeronautical Science Fund(No.2015ZE52049)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Fundamental Research Funds for the Central Universities(No.3082615NS2015056)
文摘To study the bridging effect of partly-cured Z-pin,Z-pins with different curing degrees are manufactured by controlling pultrusion parameters.A unit cell is selected to analyze the stress of Z-pinned laminates and the quantitative relationship between the maximum bridging force and Z-pin diameter,embedded length,interfacial shear strength and tensile strength is acquired.The Z-pin″bridging law″test and Z-pin tensile test are carried out to study the effect of Z-pin′s curing degree on bridging effect,and the bridging efficiency is defined to evaluate the reinforcement effect of Z-pin.The modeⅠinterlaminar fracture toughness(G_(ⅠC))is measured by the double cantilever beam test.The experimental results show that Z-pin′s co-curing with laminate matrix can improve the bridging force significantly and the fitting results show a linear relationship between Z-pin curing degree and interfacial shear strength.The three-dimensional images of the surface of pullout Z-pins indicate that the failure mode changed from totally interfacial debonding to a mixed mode.Finally,the reinforcement by partly-cured Z-pin can be used to further enhance the interlaminar toughness.Compared with completely-cured Z-pin,G_(ⅠC) of Z-pin with 67.6% curing degree increases by 47.0%.
基金This project is supported by China and Tsinghua-Zhongda Postdoctoral Science Foundation.]
文摘The bonding of solid steel to liquid aluminum was conducted using rapidsolidification. The influence of diffusion time on interfacial shear strength was studied. Theresults show that when the temperature of aluminum liquid is 700℃ and the preheat temperature ofsteel plate is 250℃, the relationship between diffusion time (t) and interfacial shear strength(σ) is σ =15.1+8.14t-037t^2 +0.005t^3, and the maximum interfacial shear strength is 71.1 MPa.
基金This project is supported by the National Natural Science Foundation of China (No.50274047) and Advanced Technical Committee of China (No. 715-009-060).
文摘The bonding of solid steel plate to liquid Al was conducted using rapid solidification. The influence of thickness of Fe-Al compound layer at the interface on interfacial shear strength of bonding plate was studied. The results show that the relationship between thickness of Fe-AI compound layer and interfacial shear strength is 5=30.4+8.51 h-0.51 h2 +0.007 h3 (where h is thickness of Fe-AI compound layer, S is interfacial shear strength). When thickness of Fe-AI compound layer is 10.7 um, the largest interfacial shear strength is 71.6 MPa.
文摘Current methodologies used for the inference of thin film stress through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. By considering a circular thin film/substrate system subject to non-uniform, but axisymmetric misfit strain distributions in the thin film, we derived relations between the film stresses and the misfit strain, and between the plate system＇s curvatures and the misfit strain. These relations feature a “local” part which involves a direct dependence of the stress or curvature components on the misfit strain at the same point, and a “non-local” part which reflects the effect of misfit strain of other points on the location of scrutiny. Most notably, we also derived relations between the polar components of the film stress and those of system curvatures which allow for the experimental inference of such stresses from full-field curvature measurements in the presence of arbitrary radial non-uniformities. These relations also feature a “non-local” dependence on curvatures making a full-field measurement a necessity. Finally, it is shown that the interfacial shear tractions between the film and the substrate are proportional to the radial gradients of the first curvature invariant and can also be inferred experimentally.
