The rheological properties of nanocellulose aqueous suspensions play a critical role in the development of nanocellulose-based bulk materials.High-crystalline,high-aspect ratio,and slender nanofibrillated cellulose(NF...The rheological properties of nanocellulose aqueous suspensions play a critical role in the development of nanocellulose-based bulk materials.High-crystalline,high-aspect ratio,and slender nanofibrillated cellulose(NFC)were extracted from four biomass resources.The cellulose nanofibrils and nanofibril bundles formed inter-connected networks in the NFC aqueous suspensions.The storage moduli of the suspensions with different concentrations were higher than their corresponding loss moduli.As the concentration increased,the storage and loss modulus of NFC dispersion increased.When the shear rate increased to a certain value,there were differences in the changing trend of the rheological behavior of NFC aqueous suspensions derived from different biomass resources and the suspensions with different solid concentrations.NFC dispersion’s storage and loss modulus increased when the temperature rose to nearly 80℃.We hope this study can deepen the understanding of the rheological properties of NFC colloids derived from different biomass resources.展开更多
This paper presents a mathematical model consisting of conservation and balance laws (CBL) of classical continuum mechanics (CCM) and ordered rate constitutive theories in Lagrangian description derived using entropy ...This paper presents a mathematical model consisting of conservation and balance laws (CBL) of classical continuum mechanics (CCM) and ordered rate constitutive theories in Lagrangian description derived using entropy inequality and the representation theorem for thermoviscoelastic solids (TVES) with rheology. The CBL and the constitutive theories take into account finite deformation and finite strain deformation physics and are based on contravariant deviatoric second Piola-Kirchhoff stress tensor and its work conjugate covariant Green’s strain tensor and their material derivatives of up to order m and n respectively. All published works on nonlinear dynamics of TVES with rheology are mostly based on phenomenological mathematical models. In rare instances, some aspects of CBL are used but are incorrectly altered to obtain mass, stiffness and damping matrices using space-time decoupled approaches. In the work presented in this paper, we show that this is not possible using CBL of CCM for TVES with rheology. Thus, the mathematical models used currently in the published works are not the correct description of the physics of nonlinear dynamics of TVES with rheology. The mathematical model used in the present work is strictly based on the CBL of CCM and is thermodynamically and mathematically consistent and the space-time coupled finite element methodology used in this work is unconditionally stable and provides solutions with desired accuracy and is ideally suited for nonlinear dynamics of TVES with memory. The work in this paper is the first presentation of a mathematical model strictly based on CBL of CCM and the solution of the mathematical model is obtained using unconditionally stable space-time coupled computational methodology that provides control over the errors in the evolution. Both space-time coupled and space-time decoupled finite element formulations are considered for obtaining solutions of the IVPs described by the mathematical model and are presented in the paper. Factors or the physics influencing dynamic response and dynamic bifurcation for TVES with rheology are identified and are also demonstrated through model problem studies. A simple model problem consisting of a rod (1D) of TVES material with memory fixed at one end and subjected to harmonic excitation at the other end is considered to study nonlinear dynamics of TVES with rheology, frequency response as well as dynamic bifurcation phenomenon.展开更多
The hydrodynamics of the capillary flow of a viscous-plastic liquid in cylindrical rectilinear pores is considered, as a result of which the structural velocity distribution over the pore cross section is obtained. An...The hydrodynamics of the capillary flow of a viscous-plastic liquid in cylindrical rectilinear pores is considered, as a result of which the structural velocity distribution over the pore cross section is obtained. Analytical solutions are proposed for the equations of hydraulic diffusion and nonlinear filtration for a non-Newtonian fluid in a cylindrical porous medium. It is noted that when a non-Newtonian fluid flows in a porous medium, the filtration equations take a nonlinear form due to the effective viscosity, shear, and yield stresses taken into account in its structure. The proposed solutions make it possible to evaluate the state of the porous medium and its main parameters (permeability, hydraulic diffusion, and effective viscosity coefficients). The obtained solutions are compared with existing experimental data for non-Newtonian oils.展开更多
As the base oil of the current flat-rheology synthetic drilling fluid is high in cost and not renewable, the biodiesel-based flat-rheology drilling fluid with low-cost, environmental protection and renewable advantage...As the base oil of the current flat-rheology synthetic drilling fluid is high in cost and not renewable, the biodiesel-based flat-rheology drilling fluid with low-cost, environmental protection and renewable advantage was studied. Based on the optimization of raw materials, a cheap, environment-friendly biodiesel of soybean oil ethyl ester with good fluidity at low temperature was selected as the base oil. By selecting high oil-water ratio and introducing cationic surfactant into the auxiliary emulsifier, the thickening of biodiesel-based emulsion caused by hydrolysis and saponification after high-temperature aging was effectively eliminated. The organoclay prepared with cationic modifier of hexadecyl trimethyl ammonium chloride was used to improve the rheologic properties, stability and fluid loss of the drilling fluid while preventing low-temperature thickening. A flat-rheology modifier was synthesized with dimer fatty acid and cocoanut fatty acid diethanolamide, which could form strong network structure in the biodiesel-based drilling fluid to adjust effectively rheological properties of the drilling fluid. A biodiesel-based flat-rheology drilling fluid system with the density of 1.2 g/cm^(3) has been formulated which has constant rheology in the temperature range of 2-90 ℃, temperature tolerance of 160 ℃, seawater salinity tolerance of 5%, shale cuttings tolerance of 10%, and is environmentally friendly.展开更多
In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,...In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,the rheological tests were carried out.These experiment results showed that the stress conditions,especially the stress level were the critical influencing factors of the rheological deformation properties.Under the low stress level(S=0.1),the granular soil showed the elastic properties,and there was no obvious rheological deformation.Under the middle stress level(0.2<S≤0.6),creep curves showed the linear viscoelastic rheological properties.However,under the high stress level(S>0.8) creep curves showed the non-linear viscous plastic rheological properties.Especially,under the stress level of S=1.0,the accelerated rheological phase of creep curves occurred at early time with a trend of failure.The stress level had obvious effects on the final rheological deformation of the soil sample,and the final rheological deformation increments nonlinearly increased with stress level.The final rheological deformation increment and step was little under low stress level,while it became large under high stress level,which showed the nonlinearly rheological properties of the granular soil.The confining pressure also had direct effects on final rheological deformation,and the final rheological deformation linearly increased with confining pressure increments.展开更多
Soft and medium-hard rocks are subjected to high rheology under high stress,and they are prone to a relatively large-degree of deformation when perturbed by external impacting loads.The phenomenon where rock deformati...Soft and medium-hard rocks are subjected to high rheology under high stress,and they are prone to a relatively large-degree of deformation when perturbed by external impacting loads.The phenomenon where rock deformation is developed due to external impacting perturbation in the rheological state is defined as the rock rheological perturbation effect.This work presents a new experimental system for investigating the rock rheological perturbation effect with experiments on medium-hard red sandstone.Results from our analysis show that red sandstone changes under two mechanical mechanisms:deformation-hardening effects at low stress states,and damage-fracture effects at high stress states when impacted by certain external impacting loads.Red sandstone tested in our experiments has a strain threshold of about 90% of the ultimate strain under the perturbation effect;the red sandstone is sensitive to a perturbed load when its actual strain exceeds the threshold.The perturbed deformation process of the rock can be divided into three phases:decline,approximately constant speed and acceleration.The rock will be rapidly destroyed when the perturbed deformation accumulates to a certain degree.The perturbation effect of rock deformation under uniaxial compression is more obvious than that under axial compression.Based on our experiment,a constitutive relation of the rock rheological perturbation effect is developed.展开更多
Waxy crude oil exhibits complex shear-and-thermal-history-dependent non-Newtonian behaviors.In the past 10 years,driven by the petroleum industry,crude oil rheology has been an active field.Studies on crude oil rheolo...Waxy crude oil exhibits complex shear-and-thermal-history-dependent non-Newtonian behaviors.In the past 10 years,driven by the petroleum industry,crude oil rheology has been an active field.Studies on crude oil rheology have been passing a way from simply relying on rheological measurements,through quantitative experimental simulation of shear and thermal history effects in pipelining,to recent development of correlation between flow properties and shear and thermal history.Currently,the study is toward quantitative inquiry of relations between the rheological behaviors and micro-structures of wax crystals as well as oil compositions.Advances achieved by the author' team are summarized,including simulation of the thermal and shear history effects,correlations and computation of flow properties,fractal characterization of morphology and structure of wax crystals,relations of rheological behaviors to fractal dimension and oil compositions,and the most successful example of the application of rheology in crude oil pipelining.Future studies are prospected.展开更多
Rheological properties of low-concentration Konjac gum and impacts of concentration,shearing rate,pH value and stirring time on its viscosity were studied.The results show that the viscosity of low-concentration Konja...Rheological properties of low-concentration Konjac gum and impacts of concentration,shearing rate,pH value and stirring time on its viscosity were studied.The results show that the viscosity of low-concentration Konjac gum increases with the increase of its concentration.The solution presents pseudo-plasticity fluid,which shows the characters of shear thinning as follows:first,its viscosity decreases gradually as the temperature increases,and then increases with the increase of temperature.The viscosity decreases sharply at both acid and alkaline conditions,indicating that it is influenced apparently by pH value.And the viscosity of low-concentration Konjac gum is also impacted by the stirring time.展开更多
Structure of emulsifiers or functionality and molecular weight determines its rheology,emulsification and stability of emulsion explosives.Rheology of typical emulsifiers was studied by automatic rheometer.Relations b...Structure of emulsifiers or functionality and molecular weight determines its rheology,emulsification and stability of emulsion explosives.Rheology of typical emulsifiers was studied by automatic rheometer.Relations between rheology and structural properties of typical emulsifiers were analyzed.Experimental results show that viscosity of emulsifiers didn't change with shear rate at room temperature and appeared properties of Newtonian fluid.Viscosity of different component emulsifiers declines with temperature in different modes.The change of strain doesn't affect modulus of emulsifiers.Loss modulus increases linearly with the increase of frequency in oscillation and storage modulus does non-linearly.The higher the temperature is,the lower change amplitude of loss modulus with frequency will be.The emulsifiers with imide and amide functionality for emulsion explosives have better shear properties at high temperature and better shapingness and stability at room temperature than other emulsifiers with ester and Sorbin Monoleate(SMO)functionality.展开更多
Petroleum and nature gas not only are important resources,but also are important strategic materials of our country.All methods the enhancing the producing degree of petroleum and natural gas reservoir,increasing sing...Petroleum and nature gas not only are important resources,but also are important strategic materials of our country.All methods the enhancing the producing degree of petroleum and natural gas reservoir,increasing single well production and extending the stimulation period of validity are important stratagem for petroleum and natural gas exploitation.Fracturing and acidizing are the main methods for stimulation as well as one of representative examples of rheology theory application in engineering.Based on analysis of low permeability reservoir characteristics,the fracturing and acidizing stimulation principles and main controlling factors were discussed.And the mechanical characteristics,chemical reaction and rheological behavior in the stimulation process were reviewed.Furthermore research trends afterwards including the material and fluid rheology in oil and natural gas production process,the deep rock fracture initiation and extension rheology,and the fracturing and acidizing application rheology were also proposed in this paper.展开更多
The present study investigates the effects of incorporating oat bran(OB) into Chinese steamed bread(CSB). Different levels(5%, 10% and 15%) of OB were used to replace wheat flour in the manufacture of CSB. The rheolog...The present study investigates the effects of incorporating oat bran(OB) into Chinese steamed bread(CSB). Different levels(5%, 10% and 15%) of OB were used to replace wheat flour in the manufacture of CSB. The rheological properties of the dough were measured(water absorption(WA), development time, mixing tolerance, extensibility and stickiness). The addition of OB significantly increased WA, development time and stickiness, whereas decreased extensibility of dough. The physical properties of CSB were determined using specific volume, loaf height, moisture, and texture analysis. The nutritional quality of the bread was also analysed using an in vitro digestion method mimicking intestinal digestion. The results illustrated that the incorporation of OB into wheat flour decreases specific volume and softness of CSB. The addition of OB decreased the glycaemic response of steamed bread.This study illustrates the potential addition of OB to improve the nutritional quality of CSB.展开更多
The average stretching direction,local rotation angular,and stretching ratio parameters of molecular trains were used to express the rheology deformation.Based on this micro geometrical deformation,the macro deformati...The average stretching direction,local rotation angular,and stretching ratio parameters of molecular trains were used to express the rheology deformation.Based on this micro geometrical deformation,the macro deformation of medium was expressed.Then,using intrinsic elasticity concept,the stress-strain relation was obtained.In this theoretic formulation,the response functions of extension ratio and rotation angular were used to express the rheology feature of medium.For medium composed by incompressible molecular trains,the local rotation angular divides rheology deformation into three kinds:viscoelastic deformation or elasticity enhancement,viscoplastic deformation or elasticity degenerate and constant elasticity range.These results explain the experimental features of rheology deformation well.展开更多
The rapeseed oil extracted from the mature seeds was purified by refining processing,and the rheological characteristic analysis of the viscosity and dynamic shear rate at gradient temperatures was made.The result sho...The rapeseed oil extracted from the mature seeds was purified by refining processing,and the rheological characteristic analysis of the viscosity and dynamic shear rate at gradient temperatures was made.The result shows that at 20,40,60 and 80 ℃ respectively,when the shear rate gradually rises,the torque increases accordingly but its viscosity does not vary distinctly.The result suggests that when rapeseed oil is used as the raw of edible oils and industries,the working procedures at high temperature will not influence its rheological characteristic distinctly.展开更多
Surface molecular motions of amorphous polymeric solids have been directly measured on the basis of scanningviscoelasticity microscopic （SVM） and lateral force microscopic （LFM） measurements. SVM and LFM measureme...Surface molecular motions of amorphous polymeric solids have been directly measured on the basis of scanningviscoelasticity microscopic （SVM） and lateral force microscopic （LFM） measurements. SVM and LFM measurements werecarried out for films of conventional monodisperse polystyrene （PS） with sec-butyl and proton-terminated end groups atroom temperature. In the case of the number-average molecular weight, M<sub>n</sub>, less than ca. 4.0×10<sup>4</sup>, the surface was in a glass-rubber transition state even though the bulk glass transition temperature, T<sub>g</sub> was far above room temperature, meaning thatthe surface molecular motion was fairly active compared with that in the bulk. LFM measurements of the, monodisperse PSfilms at various scanning rates and temperatures revealed that the time-temperature superposition was applicable to thesurface mechanical relaxation behavior and also that the surface glass transition temperature, T<sub>g</sub><sup>σ</sup>, was depressed incomparison with the bulk one even though the magnitude of M<sub>n</sub> was fairly high at 1.40×10<sup>5</sup>. The surface molecular motionof monodisperse PS with various chain end groups was investigated on the basis of temperature-dependent scanningviscoelasticity microscopy （TDSVM）. The T<sub>g</sub><sup>σ</sup>s for the PS films with M<sub>n</sub> of 4.9×10<sup>6</sup> to 1.45×10<sup>6</sup> measured by TDSVMwere smaller than those for the bulk one, with corresponding M<sub>n</sub>s, and the T<sub>g</sub><sup>σ</sup>s for M<sub>n</sub>s smaller than ca. 4.0×10<sup>4</sup> were lowerthan room temperature （293 K）. The active thermal molecular motion at the polymeric solid surface can be interpreted interms of an excess free volume near the surface region induced by the surface localization of chain end groups. In the case ofM<sub>n</sub>=ca. 5.0×10<sup>4</sup>, the T<sub>g</sub><sup>σ</sup>s for the α, ω-diamino-terminated PS （α,ω-PS（NH<sub>2</sub>）<sub>2</sub>） and α, ω-dicarboxy-terminated PS （α, ω-PS（COOH）<sub>2</sub>） films were higher than that of the PS film. The change of T<sub>g</sub><sup>σ</sup> for the PS film with various chain end groups canbe explained in terms of the depth distribution of chain end groups at the surface region depending on the relativehydrophobicity.展开更多
The rheological analysis on dynamic shear rate-viscosity relationship of tea-oil extracted from tea-oil tree seeds by supercritical extraction method was carried out at gradient temperatures and constant shear rate,re...The rheological analysis on dynamic shear rate-viscosity relationship of tea-oil extracted from tea-oil tree seeds by supercritical extraction method was carried out at gradient temperatures and constant shear rate,respectively.The results show that at 20,40,60 and 80 ℃,once the shear rate increases gradually,the torque enlarges correspondingly,while the viscosity shows little difference.However,at the constant shear rate,the rising temperature results in a steady downtrend on tea-oil viscosity.This results reveal that tea-oil viscosity is not closely correlated with shear rate at constant temperature,yet negatively correlated with temperature at constant shear rate.展开更多
Based on the rheology characteristic and the resistivity variation under alternating electric-field of Portland cement hydration by means of AR2000 advanced rheometer and non-contacting electrical resistivity device, ...Based on the rheology characteristic and the resistivity variation under alternating electric-field of Portland cement hydration by means of AR2000 advanced rheometer and non-contacting electrical resistivity device, the influence of cement kinds and the chemical admixtures on the initial rheology characteristic and structure forming and developing of cement hydration was studied. The relationship between the rheology characteristic, the initial hydration structure forming and the hydration process at very early ages was analyzed by macro properties and microstructure tests. The results showed that, the storage modulus, acted as S, could be described more subtle distinction accompanying with hydration of fresh paste model at very early period. Combining the resistivity alterations, a sudden change on structure forming emerged when the hydration of cement becoming inducing age. The rheology characteristic was interrelated to the hydration structure forming, development and the physical mechanics properties. The sudden change on storage modulus moved up due to the addition of retarder, but the structure forming and developing was retarded to a certain extent.展开更多
Trimethylsilylated silica was synthesized through hydrolytic condensation of tetraethoxysilane followed bytrimethylsilylation. Rheological properties of the silicone resin with trimethylsilylated silica as modifier we...Trimethylsilylated silica was synthesized through hydrolytic condensation of tetraethoxysilane followed bytrimethylsilylation. Rheological properties of the silicone resin with trimethylsilylated silica as modifier were studied. Itturned out that the particle size of silica was important to the rheological behavior of the modified resin. Trimethylsilylatedsilica of medium particle size shows the strongest tendency of forming physical network in the resin.展开更多
By studying and summarizing the characteristics of wood rheology,the mathematic models of creep and mechano-sorptive creep of wood were analyzed.Rheology behaviors in process,especially drying stress and deformation s...By studying and summarizing the characteristics of wood rheology,the mathematic models of creep and mechano-sorptive creep of wood were analyzed.Rheology behaviors in process,especially drying stress and deformation set were discussed.Application of wood rheology in woodcraft process was elaborated and the research prospects and orientation were forecasted.展开更多
The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in al...The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.展开更多
基金supported in part by the Fundamental Research Funds for the Central Universities(2572019BB03 and 2572021CG01)the Startup Fund and the Catalyst Fund from Rowan University and the Research Grant(PC 20-22)from the New Jersey Health Foundation from USA,and the Grant(DMR-2116353)from the National Science Foundation.
文摘The rheological properties of nanocellulose aqueous suspensions play a critical role in the development of nanocellulose-based bulk materials.High-crystalline,high-aspect ratio,and slender nanofibrillated cellulose(NFC)were extracted from four biomass resources.The cellulose nanofibrils and nanofibril bundles formed inter-connected networks in the NFC aqueous suspensions.The storage moduli of the suspensions with different concentrations were higher than their corresponding loss moduli.As the concentration increased,the storage and loss modulus of NFC dispersion increased.When the shear rate increased to a certain value,there were differences in the changing trend of the rheological behavior of NFC aqueous suspensions derived from different biomass resources and the suspensions with different solid concentrations.NFC dispersion’s storage and loss modulus increased when the temperature rose to nearly 80℃.We hope this study can deepen the understanding of the rheological properties of NFC colloids derived from different biomass resources.
文摘This paper presents a mathematical model consisting of conservation and balance laws (CBL) of classical continuum mechanics (CCM) and ordered rate constitutive theories in Lagrangian description derived using entropy inequality and the representation theorem for thermoviscoelastic solids (TVES) with rheology. The CBL and the constitutive theories take into account finite deformation and finite strain deformation physics and are based on contravariant deviatoric second Piola-Kirchhoff stress tensor and its work conjugate covariant Green’s strain tensor and their material derivatives of up to order m and n respectively. All published works on nonlinear dynamics of TVES with rheology are mostly based on phenomenological mathematical models. In rare instances, some aspects of CBL are used but are incorrectly altered to obtain mass, stiffness and damping matrices using space-time decoupled approaches. In the work presented in this paper, we show that this is not possible using CBL of CCM for TVES with rheology. Thus, the mathematical models used currently in the published works are not the correct description of the physics of nonlinear dynamics of TVES with rheology. The mathematical model used in the present work is strictly based on the CBL of CCM and is thermodynamically and mathematically consistent and the space-time coupled finite element methodology used in this work is unconditionally stable and provides solutions with desired accuracy and is ideally suited for nonlinear dynamics of TVES with memory. The work in this paper is the first presentation of a mathematical model strictly based on CBL of CCM and the solution of the mathematical model is obtained using unconditionally stable space-time coupled computational methodology that provides control over the errors in the evolution. Both space-time coupled and space-time decoupled finite element formulations are considered for obtaining solutions of the IVPs described by the mathematical model and are presented in the paper. Factors or the physics influencing dynamic response and dynamic bifurcation for TVES with rheology are identified and are also demonstrated through model problem studies. A simple model problem consisting of a rod (1D) of TVES material with memory fixed at one end and subjected to harmonic excitation at the other end is considered to study nonlinear dynamics of TVES with rheology, frequency response as well as dynamic bifurcation phenomenon.
文摘The hydrodynamics of the capillary flow of a viscous-plastic liquid in cylindrical rectilinear pores is considered, as a result of which the structural velocity distribution over the pore cross section is obtained. Analytical solutions are proposed for the equations of hydraulic diffusion and nonlinear filtration for a non-Newtonian fluid in a cylindrical porous medium. It is noted that when a non-Newtonian fluid flows in a porous medium, the filtration equations take a nonlinear form due to the effective viscosity, shear, and yield stresses taken into account in its structure. The proposed solutions make it possible to evaluate the state of the porous medium and its main parameters (permeability, hydraulic diffusion, and effective viscosity coefficients). The obtained solutions are compared with existing experimental data for non-Newtonian oils.
基金Supported by the NSFC Innovative Research Group(51821092)NSFC Foundation(52004297)+1 种基金China Postdoctoral Science Foundation(BX20200384)China University of Petroleum(Beijing)Foundation(2462020XKBH00)。
文摘As the base oil of the current flat-rheology synthetic drilling fluid is high in cost and not renewable, the biodiesel-based flat-rheology drilling fluid with low-cost, environmental protection and renewable advantage was studied. Based on the optimization of raw materials, a cheap, environment-friendly biodiesel of soybean oil ethyl ester with good fluidity at low temperature was selected as the base oil. By selecting high oil-water ratio and introducing cationic surfactant into the auxiliary emulsifier, the thickening of biodiesel-based emulsion caused by hydrolysis and saponification after high-temperature aging was effectively eliminated. The organoclay prepared with cationic modifier of hexadecyl trimethyl ammonium chloride was used to improve the rheologic properties, stability and fluid loss of the drilling fluid while preventing low-temperature thickening. A flat-rheology modifier was synthesized with dimer fatty acid and cocoanut fatty acid diethanolamide, which could form strong network structure in the biodiesel-based drilling fluid to adjust effectively rheological properties of the drilling fluid. A biodiesel-based flat-rheology drilling fluid system with the density of 1.2 g/cm^(3) has been formulated which has constant rheology in the temperature range of 2-90 ℃, temperature tolerance of 160 ℃, seawater salinity tolerance of 5%, shale cuttings tolerance of 10%, and is environmentally friendly.
基金Project(200413) supported by Communication Science and Technology Fund of Hunan Province,China
文摘In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,the rheological tests were carried out.These experiment results showed that the stress conditions,especially the stress level were the critical influencing factors of the rheological deformation properties.Under the low stress level(S=0.1),the granular soil showed the elastic properties,and there was no obvious rheological deformation.Under the middle stress level(0.2<S≤0.6),creep curves showed the linear viscoelastic rheological properties.However,under the high stress level(S>0.8) creep curves showed the non-linear viscous plastic rheological properties.Especially,under the stress level of S=1.0,the accelerated rheological phase of creep curves occurred at early time with a trend of failure.The stress level had obvious effects on the final rheological deformation of the soil sample,and the final rheological deformation increments nonlinearly increased with stress level.The final rheological deformation increment and step was little under low stress level,while it became large under high stress level,which showed the nonlinearly rheological properties of the granular soil.The confining pressure also had direct effects on final rheological deformation,and the final rheological deformation linearly increased with confining pressure increments.
基金Projects(51474218,51304127,50474029)supported by the National Natural Science Foundation of ChinaProject(2016M590646)supported by China Postdoctoral Science FoundationProject(2016121)supported by Qingdao Postdoctoral Applied Research Foundation,China
文摘Soft and medium-hard rocks are subjected to high rheology under high stress,and they are prone to a relatively large-degree of deformation when perturbed by external impacting loads.The phenomenon where rock deformation is developed due to external impacting perturbation in the rheological state is defined as the rock rheological perturbation effect.This work presents a new experimental system for investigating the rock rheological perturbation effect with experiments on medium-hard red sandstone.Results from our analysis show that red sandstone changes under two mechanical mechanisms:deformation-hardening effects at low stress states,and damage-fracture effects at high stress states when impacted by certain external impacting loads.Red sandstone tested in our experiments has a strain threshold of about 90% of the ultimate strain under the perturbation effect;the red sandstone is sensitive to a perturbed load when its actual strain exceeds the threshold.The perturbed deformation process of the rock can be divided into three phases:decline,approximately constant speed and acceleration.The rock will be rapidly destroyed when the perturbed deformation accumulates to a certain degree.The perturbation effect of rock deformation under uniaxial compression is more obvious than that under axial compression.Based on our experiment,a constitutive relation of the rock rheological perturbation effect is developed.
文摘Waxy crude oil exhibits complex shear-and-thermal-history-dependent non-Newtonian behaviors.In the past 10 years,driven by the petroleum industry,crude oil rheology has been an active field.Studies on crude oil rheology have been passing a way from simply relying on rheological measurements,through quantitative experimental simulation of shear and thermal history effects in pipelining,to recent development of correlation between flow properties and shear and thermal history.Currently,the study is toward quantitative inquiry of relations between the rheological behaviors and micro-structures of wax crystals as well as oil compositions.Advances achieved by the author' team are summarized,including simulation of the thermal and shear history effects,correlations and computation of flow properties,fractal characterization of morphology and structure of wax crystals,relations of rheological behaviors to fractal dimension and oil compositions,and the most successful example of the application of rheology in crude oil pipelining.Future studies are prospected.
基金Project(08RM05) supported by Institute of Rheological Mechanics and Material Engineering of Central South University of Forestry Technology
文摘Rheological properties of low-concentration Konjac gum and impacts of concentration,shearing rate,pH value and stirring time on its viscosity were studied.The results show that the viscosity of low-concentration Konjac gum increases with the increase of its concentration.The solution presents pseudo-plasticity fluid,which shows the characters of shear thinning as follows:first,its viscosity decreases gradually as the temperature increases,and then increases with the increase of temperature.The viscosity decreases sharply at both acid and alkaline conditions,indicating that it is influenced apparently by pH value.And the viscosity of low-concentration Konjac gum is also impacted by the stirring time.
基金Supported by Independent Research Projects of State Key Laboratory of Explosion Science and Technology(ZDKT08-05)
文摘Structure of emulsifiers or functionality and molecular weight determines its rheology,emulsification and stability of emulsion explosives.Rheology of typical emulsifiers was studied by automatic rheometer.Relations between rheology and structural properties of typical emulsifiers were analyzed.Experimental results show that viscosity of emulsifiers didn't change with shear rate at room temperature and appeared properties of Newtonian fluid.Viscosity of different component emulsifiers declines with temperature in different modes.The change of strain doesn't affect modulus of emulsifiers.Loss modulus increases linearly with the increase of frequency in oscillation and storage modulus does non-linearly.The higher the temperature is,the lower change amplitude of loss modulus with frequency will be.The emulsifiers with imide and amide functionality for emulsion explosives have better shear properties at high temperature and better shapingness and stability at room temperature than other emulsifiers with ester and Sorbin Monoleate(SMO)functionality.
基金Projects(10472134,50490274) supported by the National Natural Science Foundation of China
文摘Petroleum and nature gas not only are important resources,but also are important strategic materials of our country.All methods the enhancing the producing degree of petroleum and natural gas reservoir,increasing single well production and extending the stimulation period of validity are important stratagem for petroleum and natural gas exploitation.Fracturing and acidizing are the main methods for stimulation as well as one of representative examples of rheology theory application in engineering.Based on analysis of low permeability reservoir characteristics,the fracturing and acidizing stimulation principles and main controlling factors were discussed.And the mechanical characteristics,chemical reaction and rheological behavior in the stimulation process were reviewed.Furthermore research trends afterwards including the material and fluid rheology in oil and natural gas production process,the deep rock fracture initiation and extension rheology,and the fracturing and acidizing application rheology were also proposed in this paper.
文摘The present study investigates the effects of incorporating oat bran(OB) into Chinese steamed bread(CSB). Different levels(5%, 10% and 15%) of OB were used to replace wheat flour in the manufacture of CSB. The rheological properties of the dough were measured(water absorption(WA), development time, mixing tolerance, extensibility and stickiness). The addition of OB significantly increased WA, development time and stickiness, whereas decreased extensibility of dough. The physical properties of CSB were determined using specific volume, loaf height, moisture, and texture analysis. The nutritional quality of the bread was also analysed using an in vitro digestion method mimicking intestinal digestion. The results illustrated that the incorporation of OB into wheat flour decreases specific volume and softness of CSB. The addition of OB decreased the glycaemic response of steamed bread.This study illustrates the potential addition of OB to improve the nutritional quality of CSB.
文摘The average stretching direction,local rotation angular,and stretching ratio parameters of molecular trains were used to express the rheology deformation.Based on this micro geometrical deformation,the macro deformation of medium was expressed.Then,using intrinsic elasticity concept,the stress-strain relation was obtained.In this theoretic formulation,the response functions of extension ratio and rotation angular were used to express the rheology feature of medium.For medium composed by incompressible molecular trains,the local rotation angular divides rheology deformation into three kinds:viscoelastic deformation or elasticity enhancement,viscoplastic deformation or elasticity degenerate and constant elasticity range.These results explain the experimental features of rheology deformation well.
基金Project(2007CB210201) supported by Major State Basic Research Development Program of ChinaProject(07JJ6053) supported by Hunan Provincial Natural Science Foundation of China
文摘The rapeseed oil extracted from the mature seeds was purified by refining processing,and the rheological characteristic analysis of the viscosity and dynamic shear rate at gradient temperatures was made.The result shows that at 20,40,60 and 80 ℃ respectively,when the shear rate gradually rises,the torque increases accordingly but its viscosity does not vary distinctly.The result suggests that when rapeseed oil is used as the raw of edible oils and industries,the working procedures at high temperature will not influence its rheological characteristic distinctly.
文摘Surface molecular motions of amorphous polymeric solids have been directly measured on the basis of scanningviscoelasticity microscopic （SVM） and lateral force microscopic （LFM） measurements. SVM and LFM measurements werecarried out for films of conventional monodisperse polystyrene （PS） with sec-butyl and proton-terminated end groups atroom temperature. In the case of the number-average molecular weight, M<sub>n</sub>, less than ca. 4.0×10<sup>4</sup>, the surface was in a glass-rubber transition state even though the bulk glass transition temperature, T<sub>g</sub> was far above room temperature, meaning thatthe surface molecular motion was fairly active compared with that in the bulk. LFM measurements of the, monodisperse PSfilms at various scanning rates and temperatures revealed that the time-temperature superposition was applicable to thesurface mechanical relaxation behavior and also that the surface glass transition temperature, T<sub>g</sub><sup>σ</sup>, was depressed incomparison with the bulk one even though the magnitude of M<sub>n</sub> was fairly high at 1.40×10<sup>5</sup>. The surface molecular motionof monodisperse PS with various chain end groups was investigated on the basis of temperature-dependent scanningviscoelasticity microscopy （TDSVM）. The T<sub>g</sub><sup>σ</sup>s for the PS films with M<sub>n</sub> of 4.9×10<sup>6</sup> to 1.45×10<sup>6</sup> measured by TDSVMwere smaller than those for the bulk one, with corresponding M<sub>n</sub>s, and the T<sub>g</sub><sup>σ</sup>s for M<sub>n</sub>s smaller than ca. 4.0×10<sup>4</sup> were lowerthan room temperature （293 K）. The active thermal molecular motion at the polymeric solid surface can be interpreted interms of an excess free volume near the surface region induced by the surface localization of chain end groups. In the case ofM<sub>n</sub>=ca. 5.0×10<sup>4</sup>, the T<sub>g</sub><sup>σ</sup>s for the α, ω-diamino-terminated PS （α,ω-PS（NH<sub>2</sub>）<sub>2</sub>） and α, ω-dicarboxy-terminated PS （α, ω-PS（COOH）<sub>2</sub>） films were higher than that of the PS film. The change of T<sub>g</sub><sup>σ</sup> for the PS film with various chain end groups canbe explained in terms of the depth distribution of chain end groups at the surface region depending on the relativehydrophobicity.
基金Projects(2007CB210201) supported by the Major State Basic Research Development Program of China
文摘The rheological analysis on dynamic shear rate-viscosity relationship of tea-oil extracted from tea-oil tree seeds by supercritical extraction method was carried out at gradient temperatures and constant shear rate,respectively.The results show that at 20,40,60 and 80 ℃,once the shear rate increases gradually,the torque enlarges correspondingly,while the viscosity shows little difference.However,at the constant shear rate,the rising temperature results in a steady downtrend on tea-oil viscosity.This results reveal that tea-oil viscosity is not closely correlated with shear rate at constant temperature,yet negatively correlated with temperature at constant shear rate.
文摘Based on the rheology characteristic and the resistivity variation under alternating electric-field of Portland cement hydration by means of AR2000 advanced rheometer and non-contacting electrical resistivity device, the influence of cement kinds and the chemical admixtures on the initial rheology characteristic and structure forming and developing of cement hydration was studied. The relationship between the rheology characteristic, the initial hydration structure forming and the hydration process at very early ages was analyzed by macro properties and microstructure tests. The results showed that, the storage modulus, acted as S, could be described more subtle distinction accompanying with hydration of fresh paste model at very early period. Combining the resistivity alterations, a sudden change on structure forming emerged when the hydration of cement becoming inducing age. The rheology characteristic was interrelated to the hydration structure forming, development and the physical mechanics properties. The sudden change on storage modulus moved up due to the addition of retarder, but the structure forming and developing was retarded to a certain extent.
文摘Trimethylsilylated silica was synthesized through hydrolytic condensation of tetraethoxysilane followed bytrimethylsilylation. Rheological properties of the silicone resin with trimethylsilylated silica as modifier were studied. Itturned out that the particle size of silica was important to the rheological behavior of the modified resin. Trimethylsilylatedsilica of medium particle size shows the strongest tendency of forming physical network in the resin.
基金Project(30871983) supported by the National Natural Science Foundation of China
文摘By studying and summarizing the characteristics of wood rheology,the mathematic models of creep and mechano-sorptive creep of wood were analyzed.Rheology behaviors in process,especially drying stress and deformation set were discussed.Application of wood rheology in woodcraft process was elaborated and the research prospects and orientation were forecasted.
基金Acknowledgements--This work was supported by the National Natural Science Foundation of China （No. 503 7104 7） and the Shandong Provincial Promotional Foundation for the Excellent Middle-Aged and Young Scientists of China （No. 2005BS04012）.
文摘The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.
