Calculation of Viscosity and Diffusion Coefficients for Two Binary Gaseous Mixtures Using the Semi-empirical Inversion Method

The accurate reduced potential energies for two binary gas mixtures including benzene- methanol and methane-tetrafluoromethane at low density have been obtained by direct inversion of the viscosity collision integral equations. The kinetic theory along with the extended principle of corresponding-states has been used to calculate the viscosity and dif- fusion coefficients over a wide range of temperature and composition. Good agreements between calculated and experimental data are obtained.

Density, Viscosity, and Excess Properties for Binary Mixture of Diethylene Glycol Monoethyl Ether ＋ Water from 293.15 to 333.15 K at Atmospheric Pressure

Densities and viscosities were measured as a function of composition for binary liquid mixture of diethylerie glycol monoethyl ether [CH3CH2O（CH2）2O（CH2）2OH] ＋ water from 293.15 to 333.15 K at atmospheric pressure, with a capillary pycnometer and Ubbelohde capillary viscometer respectively. From the experimental data, the excess molar volume V^E, viscosity deviation △η, and the excess energy of activation for viscous flow △G^＊E were calculated. These data were correlated by the Redlich-Kister type equations to obtain the coefficients and standard deviations. The results showed a strong molecular interaction between diethylene glycol monoethyl ether and water.

The effect of membrane pores wettability on CO_2 removal from CO_2/CH_4 gaseous mixture using NaOH, MEA and TEA liquid absorbents in hollow fiber membrane contactor

The present paper renders a modeling and a 2D numerical simulation for the removal of CO_2from CO_2/CH_4gaseous stream utilizing sodium hydroxide(NaOH),monoethanolamine(MEA)and triethanolamine(TEA)liquid absorbents inside the hollow fiber membrane contactor.Counter-current arrangement of absorbing agents and CO_2/CH_4gaseous mixture flows are implemented in the modeling and numerical simulation.Non-wetting and partial wetting modes of operation are considered where in the partial wetting mode,CO_2/CH_4gaseous mixture and liquid absorbents fill the membrane pores.The deteriorated removal of CO_2in the partial wetting mode of operation is mainly due to the mass transfer resistance imposed by the liquid in the pores of membrane.The validation of numerical simulation is done based on the comparison of simulation results of CO_2removal using Na OH and experimental data under non-wetting mode of operation.The comparison illustrates a desirable agreement with an average deviation of less than 5%.According to the results,MEA provides higher efficiency for CO_2removal in comparison with the other liquid absorbents.The order for CO_2removal performance is MEAN Na OHN TEA.The influence of non-wetting and partial wetting modes of operation on CO_2removal are evaluated in this article as one of the novelties.Besides,the percentage of CO_2sequestration as a function of gas velocity for various percentages of membrane pores wetting ranging from 0(non-wetting mode of operation)to 100%(complete wetting mode of operation)is studied in this research paper,which can be proposed as the other novelty.The results indicate that increase in some operational parameters such as module length,membrane porosity and absorbents concentration encourage the removal percentage of CO_2from CO_2/CH_4gaseous mixture while increasing in membrane tortuosity,gas velocity and initial CO_2concentration has unfavorable influence on the separation efficiency of CO_2.

Rotational viscosity of a liquid crystal mixture: a fully atomistic molecular dynamics study

Fully atomistic molecular dynamics （MD） simulations at 293, 303 and 313 K have been performed for the four- component liquid crystal mixture, E7, using the software package Material Studio. Order parameters and orientational time correlation functions （TCFs） were calculated from MD trajectories. The rotational viscosity coefficients （RVCs） of the mixture were calculated using the Nemtsov-Zakharov and Fialkowski methods based on statistical-mechanical approaches. Temperature dependences of RVC and density were discussed in detail. Reasonable agreement between the simulated and experimental values was found.

Densities and viscosities for ionic liquids [BMIM][BF4] and [BMIM][Cl] and their binary mixtures at various temperatures and atmospheric pressure

The density and viscosity of 1-butyl-3-methylimidazolium tetrafluoroborate[BMIM][BF4]and 1-butyl-3-methylimidazolium chloride[BMIM][Cl]and their binary mixtures within the temperatures from 303.15 K to323.15 K and at ambient pressure were determined in this work.The temperature dependences of density and viscosity were satisfactorily described with the linear model and the Vogel-Tammann-Fulcher type equation,respectively.The molar volume and viscosity of binary IL mixtures were predicted through ideal mixing rules showing that almost null deviations for IL mixtures were observed and their mixing was remarkably close to linear ideal behavior in the molar volumes,while comparatively large errors in viscosity occurred.Additionally,the molar volume of the investigated pure ILs and their mixtures could well be predicted by a predictive model presented by Valderrama et al.(Fluid Phase Equilib.,275(2009)145).

A Comparative Study of the Flow Field of High Viscosity Media in Conventional/Rotary Hydrocyclones

The flow fields inside conventional and rotary hydrocyclones were simulated respectively. In these simulations, water only and oil-water mixture, with distinctly different viscosities, were used as continuous phases. Simulation results agreed well with the experimental measurements. Simulation results showed that the conventional hydrocyclone could effectively separate sand from water, but could not separate sand from high viscosity water/oil emulsion. This showed that the viscosity of continuous phases influenced greatly both the separation efficiency and the flow field distribution in the conventional hydrocyclone. For high viscosity oil/water sand dispersion （mixture）, the rotary hydrocyclone has better separation performance than the conventional one, with a more favorable flow field distribution.

Dynamics of Unsteady MHD Convective Flow with Thermophoresis of Particles and Variable Thermo-Physical Properties past a Vertical Surface Moving through Binary Mixture

The dynamics of unsteady magnetohydrodynamic convective fluid flow with radiation and thermophoresis of particles past a vertical porous plate moving through a binary mixture in an optically thin environment is investigated. The approximate form of the radiative heat flux is considered as the fourth power of temperature. Chemical reaction that occurs as the chemically reacting fluid flow through binary mixture is accounted for in energy and species concentration equations. Exponential space dependent heat source is introduced to generate additional heat energy across the fluid domain. The corresponding influence of heat energy is properly accounted for. It is assumed that viscosity and thermal conductivity vary as a linear function of temperature. The governing boundary layer equations are converted to nonlinear ordinary differential equations using similarity variables. A novel method of obtaining root finding starting with three guesses in shooting techniques is presented. The corresponding nonlinear coupled ordinary differential equations is solved numerically by shooting technique along with quadratic interpolation scheme. Graphical results of the dimensionless velocity, temperature and concentration distributions are shown for certain pertinent parameters controlling the fluid flow. The quadratic interpolation method is found to produce better estimated values of , which satisfy the degree of accuracy and proportional to the physical quantities.

Determination of physical properties for the mixtures of [BMIM]Cl with different organic solvents

Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of l-butyl- 3-methyl imidazolium chloride （[BMIM]CI） and different organic solvents at 298.15 K have been investigated. Ex- cess molar volumes have been calculated and obtained data has been fitted by the Redlich-Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]CI, however, excep- tions do exist as in the case of dimethyl sulfoxide （DMSO）/[BMIM]CI. For DMSO/[BMIM]CI, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in all mixtures studied. It has been observed that solubility parameters, dielectric constants and composition of the solvents used play a vital role in determining the resultant properties. The data obtained will play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.

Ultrasonic, Volumetric and Isentropic Compressibility of Binary Mixtures of 1,4-Dioxane with Primary Alcohols at 303.15 K

Density, viscosity and sound velocity of six binary liquid mixtures of methanol, ethanol, propanol, butanol, hexanol and octanol with 1,4-dioxane have been measured over the entire range of composition at temperature 303.15K. From the experimental densities, viscosities and sound velocity, the excess molar volume (VE), deviation in viscosity (Δη) and deviation in isentropic compressibility (ΔKS) have been calculated. The results have been used to discuss the nature and strength of intermolecular interactions in these mixtures.

Relative Explosive Strength of Some Explosive Mixtures Containing Urea and/or Peroxides

Several mixtures,based on urea derivatives and some inorganic oxidants,including also alumina,were studied by means of ballistic mortar techniques with TNT as the reference standard.The detonation pressure(P),detonation velocity(D),detonation energy(Q),and volume of gaseous product at standard temperature and pressure(STP),V,were calculated using EXPLO5V6.3 thermochemical code.The performance of the mixtures studied was discussed in relation to their thermal reactivity,determined by means of differential thermal analysis(DTA).It is shown that the presence of hydrogen peroxide in the form of its complex with urea(i.e.as UHP)has a positive influence on the explosive strength of the corresponding mixtures which is linked to the hydroxy-radical formation in the mixtures during their initiation reaction.These radicals might initiate(at least partially)powdered aluminum into oxidation in the CJ plane of the detonation wave.Mixtures containing UHP and magnesium are dangerous because of potential auto-ignition.

离子液体[EOEMIM][NTf_(2)]与甲醇二元混合物的密度和粘度性质及半经验估算

为了更好的研究离子液体二元体系的性质,同时为了离子液体的应用研究提供理论数据,本研究测定了离子液体1-乙基乙基醚-3-甲基咪唑双(三氟甲烷磺酰)亚胺盐[EOEMIM][NTf_(2)]与甲醇二元混合体系(即摩尔分数x1=0.0000~1.000)在T=(288.15~318.15)K温度范围内间隔5 K的密度值和粘度值。二元混合物的密度和粘度值随着温度T的升高而减小,随着摩尔分数的增加而增大。二元混合物的平均摩尔体积随着温度的升高而减小,随着摩尔分数的增加而增大。热膨胀系数随着温度和摩尔分数的变化缓慢。二元混合物的超额摩尔体积均是负值,Redlich-Kister方程将超额摩尔体积对摩尔分数作图,在最低点时值最小,说明此时离子液体与甲醇分子间的相互作用力最强。粘度偏差和超额粘滞流动活化Gibbs自由能分别对摩尔分数进行R-K方程拟合,拟合效果良好。结合R-K方程参数值,提出估算二元混合物任何组成的平均摩尔体积半经验方法和粘度半经验方法,二元混合物的平均摩尔体积和粘度的估算值分别与他们相对应的实验值较好的一致。

赤泥填料对排水沥青混合料路用性能的影响

为探究赤泥填料对排水沥青混合料路用性能的影响,首先选择两种国产高黏改性剂PT-HVA和AR-HVA制备得到高黏改性沥青,并将成品苯乙烯-丁二烯-苯乙烯(styrene-butadiene-styrene,SBS)改性沥青作为对照组,对三种改性沥青进行各项沥青性能试验。结果表明:两种改性剂的最佳掺量均为15%。接着以三种改性沥青为胶结料配制三种排水性沥青混合料(填料为赤泥和矿粉),并进行各项路用性能试验。结果表明:由赤泥制备的混合料的路用性能良好,其中AR-HVA高黏改性沥青+赤泥制备的混合料性能最优,动稳定度达11053次/mm,残留稳定度为91.46%,冻融劈裂比为89.60%,飞散损失为5.20%,老化系数为24.60%。同时,由赤泥制备而成的混合料的弯拉强度和弯拉应变比由矿粉制备的混合料的小,这表明赤泥虽能有效地提高混合料的高温性能、水稳性能、抗松散性能和抗老化性能,但会降低混合料的低温性能。

分子动力学模拟预测天然气密度和黏度的可行性研究

天然气作为相对清洁、低碳的能源,在我国的一次能源消费占比持续增长,其物性的精准预测对天然气集输利用过程分析至关重要。通过收集文献中天然气在不同温度和压力下的物性实测数据,对比分析了分子动力学模拟和常用经验模型计算天然气密度和黏度的预测精度,明确了不同组成天然气适用的最佳物性预测模型。结果表明,分子动力学模拟在预测天然气黏度方面具有较强的适用性,尤其是在高温高压条件下,当温度为444.4 K时,平均相对误差小于5%;天然气密度则采用现有相对成熟的经验模型更合适,而采用分子动力学模拟方法的几种力场模型预测其精度均不高;天然气密度和黏度预测模型的预测精度,不仅受温度和压力范围的影响,还与天然气组成有关。

富油型高黏高弹桥面铺装过渡层材料服役性能研究

针对混凝土桥面板铺装工程对铺装层材料的性能需求,提出富油型高黏高弹桥面铺装过渡层材料,开发出60℃黏度>70万Pa·s的过渡层材料专用高黏高弹改性沥青,研究了不同油石比、不同级配、不同厚度的过渡层材料与组合结构的服役性能规律.结果表明:富油型高黏高弹过渡层材料具备优异的高温、低温,以及水稳定性能,在组合结构的形式中与混凝土桥面板的25℃的剪切强度、拉拔强度分别达到0.98、0.71 MPa.动态荷载下,随着油石比与厚度的提高,组合结构试件的初始裂纹出现、裂缝扩展速度降低,起到阻止裂缝传递与反射的作用,在0.2应力水平下铺装层组合结构疲劳寿命可达到10万次.超薄组合铺装结构服役性能优异,可有效防止铺装层出现推移、拥包、开裂等桥面病害.

直投式高黏改性沥青混合料路用性能试验

高黏改性沥青是决定排水沥青路面使用性能的关键因素之一。为了评价改性剂类型、掺量及生产工艺的影响,分别采用车辙、半圆弯曲、浸水马歇尔、冻融劈裂和浸水肯塔堡飞散试验对高黏改性沥青混合料的高温稳定性、低温抗裂性和水稳定性进行测试,通过微观形貌特征对改性剂在沥青中的工作机理进行分析。研究结果表明:不同因素对沥青混合料空隙率的影响很小。在相同的掺量和生产工艺下,与常规的泰孚派克(Tafpack super,TPS)高黏改性沥青混合料相比,热塑性树脂(thermoplastic resin,TPR)高黏改性沥青混合料具有更优的低温抗裂性、相当的水稳定性和略差的高温稳定性,但是两者的路用性能在统计学意义上无显著差异。TPR改性剂掺量的提高可以明显提升混合料的各项路用性能;当以70#普通沥青和苯乙烯-丁二烯-苯乙烯(styrenic block copolymers,SBS)改性沥青作为基质沥青时,TPR改性剂掺量分别达到13%和9%,其混合料路用性能即可满足排水沥青混合料的技术要求。总体上看,改性剂掺量和生产工艺对各项路用性能均有显著影响,其中改性剂掺量的影响大于生产工艺。从微观形貌角度证实采用直投法时沥青中存在颗粒结团,部分改性剂颗粒与沥青的不完全混融导致直投法的改性效率低于剪切法,因此采用直投法时应适当增加改性剂掺量。研究结果可为排水沥青路面的材料设计提供有益的参考。

高黏剂对机场跑道抗车辙性能的影响研究

为探析高黏剂在沥青混合料中的应用效果,文中聚焦云南某高原机场跑道改造项目,对掺入6%高黏剂(按沥青质量计)沥青的高温和低温性能进行试验,并就沥青混合料的抗车辙能力及耐水性进行评估。结果表明,高黏剂的加入显著提高了沥青的弹性模量和与骨料的黏结力,有效提升了混合料在高温下的抗变形能力和耐水性。项目实施后,实际检测数据进一步验证了高黏剂在提升沥青及其混合料性能方面的效益。该研究成果为高黏剂在高原机场跑道加铺工程中的应用提供了科学依据,有助于提高跑道的使用性能并保障其运行安全。

高含水稠油混合液当量黏度的测试研究

原油黏度是油田地面工程集输系统规划与设计的重要物性参数。传统搅拌法测定高含水稠油混合液黏度,存在低转速无法均匀分散、高转速偏离实际工况的问题,采用高速搅拌分散与低速剪切测试交替进行,此剪切程序设计适用于高含水稠油混合液的搅拌测黏方法。此方法克服了环道法用油量大且实验操作复杂的缺点,并具备旋转黏度计连续测量且操作方便的优点。采用高低速交替搅拌法测定高含水稠油流动特性曲线,测量结果与实验环道法相比,1#油样的平均相对偏差为6.16%,平均绝对偏差为3.23 mPa·s,2#油样的平均相对偏差为2.61%,平均绝对偏差为3.69 mPa·s。结果表明:测试误差在允许范围内,测定得到的流动特性曲线呈现良好的规律性,混合液剪切稀释性随其含水率和温度降低而逐渐增强。

降黏剂对温拌沥青混合料路用性能的影响分析

文中对沥青混合料的低温性能、疲劳次数、残留强度比和残留稳定度展开试验研究。结果表明,降黏剂掺量增加过程中,温拌沥青混合料疲劳次数先增加后缓慢降低,其中掺加3%Sasobit降黏剂时为最高值,此时疲劳次数相较基质沥青高出16.3%,且温拌沥青混合料抗疲劳性能在试验范围内高于常规热拌沥青;-10℃条件下,掺加Sasobit降黏剂的温拌沥青混合料抗弯拉性能未得到明显改善,破坏弯拉应变变化幅度也较小,但弯拉破坏应变会随降黏剂掺量的增加而逐渐降低,表明降黏剂的过量掺加会对沥青混合料低温抗裂性能产生不利影响;掺加3%Sasobit降黏剂时,配制所得温拌沥青混合料具有最佳路用性能。

蚕丝/粘胶交织物表面改性对喷墨印花效果的影响

为提升墨滴在蚕丝/粘胶交织物表面的颜色性能及清晰度,采用羧甲基纤维素钠(CMC)、海藻酸钠(SA)对蚕丝/粘胶交织物进行改性处理。探究了CMC及SA对织物改性效果的影响,测试了不同工艺下改性织物表面的墨滴铺展面积和颜色性能,并通过扫描电子显微镜、红外光谱和接触角仪对改性前后织物的表观形貌、化学结构和润湿性能进行了分析。结果表明,经过CMC+SA改性后,青色和品红色墨滴铺展面积分别减小到148.1 mm^(2)和199.6 mm^(2),青色和品红色块的K/S值分别提升了8.4和11.4,表明CMC与SA填充了纤维间的孔隙,织物的润湿性增加,有效抑制墨滴在织物表面的扩散,增加了活性染料与纤维共价结合的可能性,进而改善了喷墨打印图案的效果。

不同条件下多孔沥青混合料黏结性能研究

采用高黏改性剂A对SBS改性沥青进行高黏改性,通过肯塔堡飞散试验对不同条件下的多孔沥青混合料的黏结性能进行研究。结果表明,冻融循环次数、最大公称粒径和水分的增加会增大多孔沥青混合料的飞散损失,但纤维可有效改善多孔沥青混合料的飞散损失。当冻融循环次数为1和8次时,PAC-16的飞散损失分别较PAC-13增大17.60%和3.90%,含纤维PAC-13的飞散损失分别较不含纤维PAC-13的减少15.34%和17.94%,有水试验试件的飞散损失分别较无水状态下增大18.58%和36.63%。