The coupled effect of viscosity enhancing admixtures(VEA)and superplasticizer(SP)on the rheological behavior of cement paste was investigated in this work.Two types of VEAs,including hydroxypropyl methylcellulose(HPMC...The coupled effect of viscosity enhancing admixtures(VEA)and superplasticizer(SP)on the rheological behavior of cement paste was investigated in this work.Two types of VEAs,including hydroxypropyl methylcellulose(HPMC)and Welan gum,and two types of SPs,i.e.polycarboxylate(PCA)and polynaphthalenesulfonate(PNS)were used as admixtures for cement paste.Rheological curves of cement paste and simulated pore solution containing VEA and SP were tested.Simulated pore solution test results show that molecules of different SPs may generate different effects on the viscosity of VEA solutions.Hershel-Bulkley(H-B)model was used to fit rheological curve of cement paste.Strong interaction between PNS and HPMC was observed in this work.展开更多
Poly-L-lactide（PLLA） was synthesized by ring-opening polymerization fi＇om high purity L-lactide with tin octoate as initiator, and characterized by means of infi＇ared, and ^1H-nuclear magnetic resonance. The influ...Poly-L-lactide（PLLA） was synthesized by ring-opening polymerization fi＇om high purity L-lactide with tin octoate as initiator, and characterized by means of infi＇ared, and ^1H-nuclear magnetic resonance. The influences of initiator concentration, polymerization temperature and polymerization time on the viscosity average molecular mass of PLLA were investigated. The effects of different purification methods on the concentration of initiator and viscosity average molecular mass were also studied. PLLA with a viscosity average molecular mass of about 50.5×1^04 was obtained when polymerization was conducted for 24 h at 140℃ with the molar ratio of monomer to purification initator being 12 000. After purification, the concentration of tin octoate decreases; however, the effect of different purification methods on the viscosity average molecular mass of PLLA is different, and the obtained PLLA is a typical amorphous polymeric material. The crystallinity of PLLA decreases with the increase of viscosity average molecular mass.展开更多
The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by...The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation,and the mechanism of increasing polymer viscosity was investigated.The experimental results also show that there is a critical concentration of 15 mg/L.Below it,the loss rate of HPAM solution viscosity increases more rapidly,but becomes slowly above the critical concentration.A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide,and it is also importance to prepare polymer solution using sewage-water and save fresh water.展开更多
High-viscosity dispersing system is formed by dispersing the solid particles in the high-viscosity continuous medium.It is very easy to form the three-dimensional network structure for solid particles in the system an...High-viscosity dispersing system is formed by dispersing the solid particles in the high-viscosity continuous medium.It is very easy to form the three-dimensional network structure for solid particles in the system and the rheology behavior becomes complicated.The apparent viscosity of this dispersing system always has the connection with the volume ratio and the shear rate.In order to discuss the rheology behavior and put up the viscosity model,the suspension of silicon dioxide and silicon oil were prepared.Through testing the viscosity,the solid concentration and the shear rate,the effects of the ratio and the shear rate on viscosity was analyzed,the model of the high-viscosity dispersing system was designed and the model with the printing ink were validated.The experiment results show that the model is applicable to the high-viscosity dispersing systems.展开更多
A series of experiments were performed on the viscosity of a nanofluid,produced by mixing carbon black and mulsifier OP-10 using ammonia-water with the ultrasonic dispersion.The results show that,when adding surfactan...A series of experiments were performed on the viscosity of a nanofluid,produced by mixing carbon black and mulsifier OP-10 using ammonia-water with the ultrasonic dispersion.The results show that,when adding surfactant separately in low mass concentrations,at first the viscosity of solution decreases sharply compared with that of ammonia-water,then increases with increasing the concentration of OP-10.In a certain concentration of surfactant,the viscosity of nanofluids increases with increasing the concentration of nanoparticles.Based on Einstein model and Langmuir absorption theory,a new model was summed up for nanofluids.Compared with test values,the calculated values on the new model have verified that the model is suitable to predict the viscosity of nanofluids,because the maximum relative error is less than 5%.Nano-particles absorption in the nanofluids is not only single-molecule layer adsorption,but also multi-layer molecular adsorption and other complicated adsorption.So the new model,only based on single-molecule layer adsorption theory of Langmuir,is not fully in line with the real circumstances.展开更多
A further numerical study of the theory that the drag reduction in the turbulence is related to the viscosity profile growing linearly with the distance from the wall was performed.The constant viscosity in the Navier...A further numerical study of the theory that the drag reduction in the turbulence is related to the viscosity profile growing linearly with the distance from the wall was performed.The constant viscosity in the Navier-Stokes equations was replaced using this viscosity model.Some drag reduction characteristics were shown comparing with Virk's phenomenology.The mean velocity and Reynolds stress profiles are consistent with the experimental and direct numerical simulation results.A drag reduction level of 45% was obtained.It is reasonable for this linear viscosity model to explain the mechanism of turbulence drag reduction in some aspects.展开更多
The dynamic analysis of semi-flexible polymers,such as DNA molecules,is an important multiscale problem with a wide range of applications in science and bioengineering.In this contribution,a dumbbell model with intern...The dynamic analysis of semi-flexible polymers,such as DNA molecules,is an important multiscale problem with a wide range of applications in science and bioengineering.In this contribution,a dumbbell model with internal viscosity was studied in steady shear flows of polymeric fluid.The tensors with moments other than second moment were approximated in the terms of second moment tensor.Then,the nonlinear algebraic equation of the second moment conformation tensor was calculated in closed form.Finally,substituting the resulting conformation tensor into the Kramers equation of Hookean spring force,the constitutive equations were obtained.The shear material properties were discussed for different internal viscosities and compared with the results of Brownian dynamics simulation.展开更多
The effect of temperature and metal ion components on the viscosity of HPAM solution was studied by means of orthogonal method.Five factors and 4 levels were considered for the orthogonal design.The five factors inclu...The effect of temperature and metal ion components on the viscosity of HPAM solution was studied by means of orthogonal method.Five factors and 4 levels were considered for the orthogonal design.The five factors included temperature,contents of Na+,Mg2+,Ca2+ and S2-,and the four levels mainly considered the level of produced water components in main oilfields in China.The experiment results show that temperature is the most important factor to control HPAM solution viscosity prepared by produced water.The effect of ions was in order of Na+>S2->Mg2+>Ca2+.The mechanism of each factor influencing viscosity was also discussed.Based on the actual condition of Nanyang oilfield,the desulfurization was used to improve the solution viscosity,and satisfactory result was obtained.展开更多
Protein folding involves the aminoacid sequence to come forth and form an energy minimized structure.Recently molecular crowding leading to increase in viscosity is said to be one of the major concerns affecting prote...Protein folding involves the aminoacid sequence to come forth and form an energy minimized structure.Recently molecular crowding leading to increase in viscosity is said to be one of the major concerns affecting protein folding.Many external fluorescent probes are used to detect such increases in viscosity.Since most of the protein sequences contain L-Phe and L-Trp,in this study we have used these aminoacids as probes to detect changes in viscosity.This study will help to advance the knowledge on molecular crowding effects in protein folding.展开更多
The biological variety is mainly connected with presence of the field ecosites,which determine the mechanism of interaction(the symbiosis,pathogenesis,and etc.) that differ typically of such
This paper describes the principle of measuring the pressure-viscosity relation in mineral oil by the capillary method, and the ftrst experimental equipment for measuring the pressure-viscosity relation in our country...This paper describes the principle of measuring the pressure-viscosity relation in mineral oil by the capillary method, and the ftrst experimental equipment for measuring the pressure-viscosity relation in our country—type NY-1 capillary pressuer-viscosity equipment, which is designed by the authors. The experimental investigation into four kinds of mineral oil is completed on the equipment. The range of pressure is 0 to 0.1 GPa. The experimental results show that the pressure-viscosity relations in the four kinds of mineral oil agree with the Barus equation.展开更多
The viscous-flow properties of pectin from the residue of orange peel after extraction of essential oil and flavonoid were studied and the viscosity-average molecular mass(Mv,ave) of this kind of pectin was determined...The viscous-flow properties of pectin from the residue of orange peel after extraction of essential oil and flavonoid were studied and the viscosity-average molecular mass(Mv,ave) of this kind of pectin was determined.Experimental results show that Arrhenius viscous-flow equation can be applied to describing the effect of temperature on viscosity of this kind of orange peel pectin solutions with the average viscous-flow activation energy being 17.91 kJ/mol(depending on the concentration).Neither power equation,η =K1 cA1,nor exponential equation,η=K2exp(A2c) can describe the effect of concentration on viscosity of this kind of orange peel pectin solutions well.However,it seems that exponential equation model is more suitable to describe their relation due to its higher linear correlation coefficient.Schulz-Blaschke equation can be used to calculate the intrinsic viscosity of this kind of orange peel pectin.The Mv,ave of the orange peel pectin is 1.65×105 g/mol.展开更多
针对稠油热采存在油汽比低、能耗大、CO_(2)排放高以及稠油冷采采出液难处理等问题,采用自制的降黏驱油剂ODA1配制驱替液,对其进行了静态降黏评价、性能分析以及特稠油冷采物理模拟实验研究。结果表明:提高驱替液中ODA1的质量分数和矿化...针对稠油热采存在油汽比低、能耗大、CO_(2)排放高以及稠油冷采采出液难处理等问题,采用自制的降黏驱油剂ODA1配制驱替液,对其进行了静态降黏评价、性能分析以及特稠油冷采物理模拟实验研究。结果表明:提高驱替液中ODA1的质量分数和矿化度,均能有效降低稠油黏度;当驱替液中ODA1质量分数为2%、矿化度为100 g/L时,特稠油与驱替液以质量比为0.5混合后的降黏率达到了70.62%;特稠油在驱替液表面自发扩散,油水自动分相,完全不乳化。在渗透率约为1 000×10^(-3)μm^(2)、地层温度为40℃、特稠油黏度为11 600 m Pa·s条件下进行模拟驱油实验,驱替液驱的采出程度较模拟地层水驱采出程度提高了6.31百分点;水驱后驱替液依次进行转驱、第1次闷井和第2次闷井,采出程度分别提高了7.48、11.70和7.83百分点,合计较水驱提高了27.02百分点,采出稠油在40℃条件下的黏度降至3 553 m Pa·s,降黏率达61.37%,驱替液具有边驱油边降黏的特点。同时在冷采过程中无碳排放,采出水无污染,可循环利用。研究成果为特稠油绿色冷采提供了一种新的技术思路。展开更多
基金Project(2017YFB0310101)supported by National High Technology Research and Development Program of ChinaProject(51778269)supported by the National Natural Science Foundation of China
文摘The coupled effect of viscosity enhancing admixtures(VEA)and superplasticizer(SP)on the rheological behavior of cement paste was investigated in this work.Two types of VEAs,including hydroxypropyl methylcellulose(HPMC)and Welan gum,and two types of SPs,i.e.polycarboxylate(PCA)and polynaphthalenesulfonate(PNS)were used as admixtures for cement paste.Rheological curves of cement paste and simulated pore solution containing VEA and SP were tested.Simulated pore solution test results show that molecules of different SPs may generate different effects on the viscosity of VEA solutions.Hershel-Bulkley(H-B)model was used to fit rheological curve of cement paste.Strong interaction between PNS and HPMC was observed in this work.
基金Project (50174059) supported by the National Natural Science Foundation of China
文摘Poly-L-lactide（PLLA） was synthesized by ring-opening polymerization fi＇om high purity L-lactide with tin octoate as initiator, and characterized by means of infi＇ared, and ^1H-nuclear magnetic resonance. The influences of initiator concentration, polymerization temperature and polymerization time on the viscosity average molecular mass of PLLA were investigated. The effects of different purification methods on the concentration of initiator and viscosity average molecular mass were also studied. PLLA with a viscosity average molecular mass of about 50.5×1^04 was obtained when polymerization was conducted for 24 h at 140℃ with the molar ratio of monomer to purification initator being 12 000. After purification, the concentration of tin octoate decreases; however, the effect of different purification methods on the viscosity average molecular mass of PLLA is different, and the obtained PLLA is a typical amorphous polymeric material. The crystallinity of PLLA decreases with the increase of viscosity average molecular mass.
基金Project(200873181) supported by NSFCProject(2007AA06Z214) supported by the High-tech Research and Development Program of ChinaProject(20070704) supported by Taishan Scholars Construction Engineering
文摘The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation,and the mechanism of increasing polymer viscosity was investigated.The experimental results also show that there is a critical concentration of 15 mg/L.Below it,the loss rate of HPAM solution viscosity increases more rapidly,but becomes slowly above the critical concentration.A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide,and it is also importance to prepare polymer solution using sewage-water and save fresh water.
文摘High-viscosity dispersing system is formed by dispersing the solid particles in the high-viscosity continuous medium.It is very easy to form the three-dimensional network structure for solid particles in the system and the rheology behavior becomes complicated.The apparent viscosity of this dispersing system always has the connection with the volume ratio and the shear rate.In order to discuss the rheology behavior and put up the viscosity model,the suspension of silicon dioxide and silicon oil were prepared.Through testing the viscosity,the solid concentration and the shear rate,the effects of the ratio and the shear rate on viscosity was analyzed,the model of the high-viscosity dispersing system was designed and the model with the printing ink were validated.The experiment results show that the model is applicable to the high-viscosity dispersing systems.
基金Supported by National Natural Science Foundation of China(50876020)
文摘A series of experiments were performed on the viscosity of a nanofluid,produced by mixing carbon black and mulsifier OP-10 using ammonia-water with the ultrasonic dispersion.The results show that,when adding surfactant separately in low mass concentrations,at first the viscosity of solution decreases sharply compared with that of ammonia-water,then increases with increasing the concentration of OP-10.In a certain concentration of surfactant,the viscosity of nanofluids increases with increasing the concentration of nanoparticles.Based on Einstein model and Langmuir absorption theory,a new model was summed up for nanofluids.Compared with test values,the calculated values on the new model have verified that the model is suitable to predict the viscosity of nanofluids,because the maximum relative error is less than 5%.Nano-particles absorption in the nanofluids is not only single-molecule layer adsorption,but also multi-layer molecular adsorption and other complicated adsorption.So the new model,only based on single-molecule layer adsorption theory of Langmuir,is not fully in line with the real circumstances.
基金Project(10672069) supported by the National Natural Science Foundation of China
文摘A further numerical study of the theory that the drag reduction in the turbulence is related to the viscosity profile growing linearly with the distance from the wall was performed.The constant viscosity in the Navier-Stokes equations was replaced using this viscosity model.Some drag reduction characteristics were shown comparing with Virk's phenomenology.The mean velocity and Reynolds stress profiles are consistent with the experimental and direct numerical simulation results.A drag reduction level of 45% was obtained.It is reasonable for this linear viscosity model to explain the mechanism of turbulence drag reduction in some aspects.
基金Project(10702045) supported by the National Natural Science Foundation of China
文摘The dynamic analysis of semi-flexible polymers,such as DNA molecules,is an important multiscale problem with a wide range of applications in science and bioengineering.In this contribution,a dumbbell model with internal viscosity was studied in steady shear flows of polymeric fluid.The tensors with moments other than second moment were approximated in the terms of second moment tensor.Then,the nonlinear algebraic equation of the second moment conformation tensor was calculated in closed form.Finally,substituting the resulting conformation tensor into the Kramers equation of Hookean spring force,the constitutive equations were obtained.The shear material properties were discussed for different internal viscosities and compared with the results of Brownian dynamics simulation.
基金Project(2007AA06Z214) supported by the National High-Tech Research and Development Program of ChinaProject(ts20070704) supported by Taishan Scholars Construction EngineeringProject(200873181) supported by National Natural Science Foundation of China
文摘The effect of temperature and metal ion components on the viscosity of HPAM solution was studied by means of orthogonal method.Five factors and 4 levels were considered for the orthogonal design.The five factors included temperature,contents of Na+,Mg2+,Ca2+ and S2-,and the four levels mainly considered the level of produced water components in main oilfields in China.The experiment results show that temperature is the most important factor to control HPAM solution viscosity prepared by produced water.The effect of ions was in order of Na+>S2->Mg2+>Ca2+.The mechanism of each factor influencing viscosity was also discussed.Based on the actual condition of Nanyang oilfield,the desulfurization was used to improve the solution viscosity,and satisfactory result was obtained.
文摘Protein folding involves the aminoacid sequence to come forth and form an energy minimized structure.Recently molecular crowding leading to increase in viscosity is said to be one of the major concerns affecting protein folding.Many external fluorescent probes are used to detect such increases in viscosity.Since most of the protein sequences contain L-Phe and L-Trp,in this study we have used these aminoacids as probes to detect changes in viscosity.This study will help to advance the knowledge on molecular crowding effects in protein folding.
文摘The biological variety is mainly connected with presence of the field ecosites,which determine the mechanism of interaction(the symbiosis,pathogenesis,and etc.) that differ typically of such
文摘This paper describes the principle of measuring the pressure-viscosity relation in mineral oil by the capillary method, and the ftrst experimental equipment for measuring the pressure-viscosity relation in our country—type NY-1 capillary pressuer-viscosity equipment, which is designed by the authors. The experimental investigation into four kinds of mineral oil is completed on the equipment. The range of pressure is 0 to 0.1 GPa. The experimental results show that the pressure-viscosity relations in the four kinds of mineral oil agree with the Barus equation.
基金Project(104-0071) supported by Foundation of Talents of Central South University of Forestry and Technology,China
文摘The viscous-flow properties of pectin from the residue of orange peel after extraction of essential oil and flavonoid were studied and the viscosity-average molecular mass(Mv,ave) of this kind of pectin was determined.Experimental results show that Arrhenius viscous-flow equation can be applied to describing the effect of temperature on viscosity of this kind of orange peel pectin solutions with the average viscous-flow activation energy being 17.91 kJ/mol(depending on the concentration).Neither power equation,η =K1 cA1,nor exponential equation,η=K2exp(A2c) can describe the effect of concentration on viscosity of this kind of orange peel pectin solutions well.However,it seems that exponential equation model is more suitable to describe their relation due to its higher linear correlation coefficient.Schulz-Blaschke equation can be used to calculate the intrinsic viscosity of this kind of orange peel pectin.The Mv,ave of the orange peel pectin is 1.65×105 g/mol.
文摘针对稠油热采存在油汽比低、能耗大、CO_(2)排放高以及稠油冷采采出液难处理等问题,采用自制的降黏驱油剂ODA1配制驱替液,对其进行了静态降黏评价、性能分析以及特稠油冷采物理模拟实验研究。结果表明:提高驱替液中ODA1的质量分数和矿化度,均能有效降低稠油黏度;当驱替液中ODA1质量分数为2%、矿化度为100 g/L时,特稠油与驱替液以质量比为0.5混合后的降黏率达到了70.62%;特稠油在驱替液表面自发扩散,油水自动分相,完全不乳化。在渗透率约为1 000×10^(-3)μm^(2)、地层温度为40℃、特稠油黏度为11 600 m Pa·s条件下进行模拟驱油实验,驱替液驱的采出程度较模拟地层水驱采出程度提高了6.31百分点;水驱后驱替液依次进行转驱、第1次闷井和第2次闷井,采出程度分别提高了7.48、11.70和7.83百分点,合计较水驱提高了27.02百分点,采出稠油在40℃条件下的黏度降至3 553 m Pa·s,降黏率达61.37%,驱替液具有边驱油边降黏的特点。同时在冷采过程中无碳排放,采出水无污染,可循环利用。研究成果为特稠油绿色冷采提供了一种新的技术思路。
