当前位置：文档之家 › VISCOSITY OF LIQUIDS

VISCOSITY OF LIQUIDS

  • 格式：pdf
  • 大小：155.80 KB
  • 文档页数：5

VISCOSITY OF LIQUIDSThe absolute viscosity of some common liquids at temperatures between –25 and 100°C is given in this table. Values were derived by fitting experimental data to suitable expressions for the tem-perature dependence. The substances are arranged by molecular formula in the modified Hill order (see Preface). All values are given in units of millipascal seconds (mPa s); this unit is identical to centipoise (cp).Viscosity values correspond to a nominal pressure of 1 atmos-phere. If a value is given at a temperature above the normal boiling point, the applicable pressure is understood to be the vapor pres-sure of the liquid at that temperature. A few values are given at a temperature slightly below the normal freezing point; these refer to the supercooled liquid.The accuracy ranges from 1% in the best cases to 5 to 10% in the worst cases. Additional significant figures are included in the table to facilitate interpolation.References1. Viswanath, D. S. and Natarajan, G., Data Book on the Viscosity of Liquids, Hemisphere Publishing Corp., New York, 1989.2. Daubert, T. E., Danner, R. P., Sibul, H. M., and Stebbins, C. C., Physical and Thermodynamic Properties of Pure Compounds: Data Compilation, extant 1994 (core with 4 supplements), Taylor & Francis, Bristol, PA (also available as database).3. Ho, C. Y., Ed., CINDAS Data Series on Material Properties, Vol. V-1, Properties of Inorganic and Organic Fluids, Hemisphere Publishing Corp., New York, 1988.4. Stephan, K. and Lucas, K., Viscosity of Dense Fluids, Plenum Press, New York, 1979.5. Vargaftik, N. B., Tables of Thermophysical Properties of Liquids and Gases, 2nd ed., John Wiley, New York, 1975.Molecularformula NameViscosity in mPa s–25°C0°C25°C50°C75°C100°CCompounds not containing carbonBr2Bromine 1.2520.9440.746Cl3HSi Trichlorosilane0.4150.326Cl3P Phosphorous trichloride0.8700.6620.5290.439Cl4Si Tetrachlorosilane99.496.2H2O Water 1.7930.8900.5470.3780.282H4N2Hydrazine0.8760.6280.4800.384Hg Mercury 1.526 1.402 1.312 1.245NO2Nitrogen dioxide0.5320.402Compounds containing carbonCCl3F Trichlorofluoromethane0.7400.5390.421CCl4Tetrachloromethane 1.3210.9080.6560.494CS2Carbon disulfide0.4290.352CHBr3Tribromomethane 1.857 1.367 1.029CHCl3Trichloromethane0.9880.7060.5370.427CHN Hydrogen cyanide0.2350.183CH2Br2Dibromomethane 1.948 1.3200.9800.7790.652CH2Cl2Dichloromethane0.7270.5330.413CH2O2Formic acid 1.607 1.0300.7240.545CH3I Iodomethane0.5940.469CH3NO Formamide7.114 3.343 1.833CH3NO2Nitromethane 1.3110.8750.6300.4810.3830.317CH4O Methanol 1.2580.7930.544CH5N Methylamine0.3190.231C2Cl3F31,1,2-Trichlorotrifluoro-ethane 1.4650.9450.6560.481C2Cl4Tetrachloroethylene 1.1140.8440.6630.5350.442C2HCl3Trichloroethylene0.7030.5450.4440.376C2HCl5Pentachloroethane 3.761 2.254 1.491 1.061C2HF3O2Trifluoroacetic acid0.8080.571C2H2Cl2cis-1,2-Dichloroethylene0.7860.5750.445C2H2Cl2trans-1,2-Dichloroethylene0.5220.3980.3170.261C2H2Cl41,1,1,2-Tetrachloroethane 3.660 2.200 1.437 1.0060.7410.570C2H3ClF21-Chloro-1,1-difluoro-ethane0.4770.376C2H3ClO Acetyl chloride0.3680.294C2H3Cl31,1,1-Trichloroethane 1.847 1.1610.7930.5780.428C2H3N Acetonitrile0.4000.3690.2840.234C2H4Br21,2-Dibromoethane 1.595 1.1160.8370.6616-175Molecularformula NameViscosity in mPa s–25°C0°C25°C50°C75°C100°CC2H4Cl21,1-Dichloroethane0.4640.362C2H4Cl21,2-Dichloroethane 1.1250.7790.5760.447C2H4O2Acetic acid 1.0560.7860.5990.464C2H4O2Methyl formate0.4240.325C2H5Br Bromoethane0.6350.4770.374C2H5Cl Chloroethane0.4160.319C2H5I Iodoethane0.7230.5560.4440.365C2H5NO N-Methylformamide 2.549 1.678 1.1550.8240.606C2H5NO2Nitroethane 1.3540.9400.6880.5260.4150.337C2H6O Ethanol 3.262 1.786 1.0740.6940.476C2H6OS Dimethyl sulfoxide 1.987 1.290C2H6O2Ethylene glycol16.1 6.554 3.340 1.975C2H6S Dimethyl sulfide0.3560.284C2H6S Ethanethiol0.3640.287C2H7N Dimethylamine0.3000.232C2H7NO Ethanolamine21.18.560 3.935 1.998C3H5Br3-Bromopropene0.6200.4710.373C3H5Cl3-Chloropropene0.4080.314C3H5ClO Epichlorohydrin 2.492 1.570 1.0730.7810.5970.474C3H5N Propanenitrile0.2940.2400.202C3H6O Acetone0.5400.3950.3060.247C3H6O Allyl alcohol 1.2180.7590.505C3H6O Propanal0.3210.249C3H6O2Ethyl formate0.5060.3800.300C3H6O2Methyl acetate0.4770.3640.284C3H6O2Propanoic acid 1.499 1.0300.7490.5690.449C3H7Br1-Bromopropane0.6450.4890.387C3H7Br2-Bromopropane0.6120.4580.359C3H7Cl1-Chloropropane0.4360.334C3H7Cl2-Chloropropane0.4010.303C3H7I1-Iodopropane0.9700.7030.5410.4360.363C3H7I2-Iodopropane0.8830.6530.5060.407C3H7NO N,N-Dimethylformamide 1.1760.7940.624C3H7NO21-Nitropropane 1.851 1.1600.7980.5890.4600.374C3H8O1-Propanol8.645 3.815 1.945 1.1070.685C3H8O2-Propanol 4.619 2.038 1.0280.576C3H8O21,2-Propylene glycol24840.411.3 4.770 2.750C3H8O3Glycerol93415239.814.8C3H8S1-Propanethiol0.5030.385C3H8S2-Propanethiol0.4770.3570.280C3H9N Propylamine0.376C3H9N Isopropylamine0.4540.325C4H4O Furan0.6610.4750.361C4H5N Pyrrole 2.085 1.2250.8280.612C4H6O3Acetic anhydride 1.2410.8430.6140.4720.377C4H7N Butanenitrile0.5530.4180.3300.268C4H8O2-Butanone0.7200.5330.4050.3150.249C4H8O Tetrahydrofuran0.8490.6050.4560.359C4H8O21,4-Dioxane 1.1770.7870.569C4H8O2Ethyl acetate0.5780.4230.3250.259C4H8O2Methyl propionate0.5810.4310.3330.266C4H8O2Propyl formate0.6690.4850.3700.293C4H8O2Butanoic acid 2.215 1.4260.9820.7140.542C4H8O22-Methylpropanoic acid 1.857 1.2260.8630.6390.492C4H8O2S Sulfolane 6.280 3.818 2.559C4H8S Tetrahydrothiophene0.9730.912C4H9Br1-Bromobutane0.8150.6060.4710.379C4H9Cl1-Chlorobutane0.5560.4220.3290.261C4H9N Pyrrolidine 1.914 1.0710.7040.512C4H9NO N,N-Dimethylacetamide 1.9276-176 Viscosity of LiquidsMolecularformula NameViscosity in mPa s–25°C0°C25°C50°C75°C100°CC4H9NO Morpholine 2.021 1.2470.8500.627C4H10O1-Butanol12.19 5.185 2.544 1.3940.8330.533C4H10O2-Butanol 3.096 1.3320.6980.419C4H10O2-Methyl-2-propanol 4.312 1.4210.678C4H10O Diethyl ether0.2830.224C4H10O3Diethylene glycol30.20011.130 4.917 2.505C4H10S Diethyl sulfide0.5580.4220.3310.267C4H11N Butylamine0.8300.5740.4090.298C4H11N Isobutylamine0.7700.5710.367C4H11N Diethylamine0.3190.239C4H11NO2Diethanolamine109.528.79.100C5H4O2Furfural 2.501 1.587 1.1430.9060.772C5H5N Pyridine 1.3610.8790.6370.4970.409C5H101-Pentene0.3130.2410.195C5H102-Methyl-2-butene0.2550.203C5H10Cyclopentane0.5550.4130.321C5H10O Mesityl oxide 1.2910.8380.6020.4650.3810.326C5H10O2-Pentanone0.6410.4700.3620.2890.238C5H10O3-Pentanone0.5920.4440.3450.2760.227C5H10O2Butyl formate0.9370.6440.4720.3620.289C5H10O2Propyl acetate0.7680.5440.4060.3160.255C5H10O2Ethyl propanoate0.6910.5010.3800.2990.242C5H10O2Methyl butanoate0.7590.5410.4060.3180.257C5H10O2Methyl isobutanoate0.6720.4880.3730.296C5H11N Piperidine 1.5730.9580.6490.474C5H12Pentane0.3510.2740.224C5H12Isopentane0.3760.2770.214C5H12O1-Pentanol25.48.512 3.619 1.820 1.0350.646C5H12O2-Pentanol 3.470 1.4470.7610.465C5H12O3-Pentanol 4.149 1.4730.7270.436C5H12O2-Methyl-1-butanol 4.453 1.963 1.0310.612C5H12O3-Methyl-1-butanol8.627 3.692 1.842 1.0310.631C5H13N Pentylamine 1.0300.7020.4930.356C6F6Hexafluorobenzene 2.789 1.730 1.151C6H4Cl2o-Dichlorobenzene 1.958 1.3240.9620.7390.593C6H4Cl2m-Dichlorobenzene 1.492 1.0440.7870.6280.525C6H5Br Bromobenzene 1.560 1.0740.7980.6270.512C6H5Cl Chlorobenzene 1.703 1.0580.7530.5750.4560.369C6H5ClO o-Chlorophenol 3.589 1.835 1.1310.786C6H5ClO m-Chlorophenol 4.041C6H5F Fluorobenzene0.7490.5500.4230.338C6H5I Iodobenzene 2.354 1.554 1.1170.8540.683C6H5NO2Nitrobenzene 3.036 1.863 1.2620.9180.704C6H6Benzene0.6040.4360.335C6H6ClN o-Chloroaniline 3.316 1.913 1.2480.887C6H6O Phenol 3.437 1.784 1.099C6H7N Aniline 3.847 2.029 1.2470.850C6H8N2Phenylhydrazine13.0 4.553 1.8500.848C6H10Cyclohexene0.8820.6250.4670.364C6H10O Cyclohexanone 2.017 1.3210.9190.671C6H11N Hexanenitrile0.9120.6500.4880.382C6H12Cyclohexane0.8940.6150.447C6H12Methylcyclopentane0.9270.6530.4790.364C6H121-Hexene0.4410.3260.2520.202C6H12O Cyclohexanol57.512.3 4.274 1.982C6H12O2-Hexanone 1.3000.8400.5830.4290.3290.262C6H12O4-Methyl-2-pentanone0.5450.406C6H12O2Butyl acetate 1.0020.6850.5000.3830.305C6H12O2Isobutyl acetate0.6760.4930.3700.286C6H12O2Ethyl butanoate0.6390.453Viscosity of Liquids 6-177Molecularformula NameViscosity in mPa s–25°C0°C25°C50°C75°C100°CC6H12O2Diacetone alcohol28.7 6.621 2.798 1.829 1.648C6H12O3Paraldehyde 1.0790.6920.4850.362C6H13N Cyclohexylamine 1.944 1.1690.7820.565C6H14Hexane0.4050.3000.240C6H142-Methylpentane0.3720.2860.226C6H143-Methylpentane0.3950.306C6H14O Dipropyl ether0.5420.3960.3040.242C6H14O1-Hexanol 4.578 2.271 1.2700.781C6H15N Triethylamine0.4550.3470.2730.221C6H15N Dipropylamine0.7510.5170.3770.2880.228C6H15N Diisopropylamine0.3930.3000.237C6H15NO3Triethanolamine60911431.511.7C7H5N Benzonitrile 1.2670.8830.6620.524C7H7Cl o-Chlorotoluene 1.3900.9640.7100.5470.437C7H7Cl m-Chlorotoluene 1.1650.8230.6160.4820.391C7H7Cl p-Chlorotoluene0.8370.6210.4830.390C7H8Toluene 1.1650.7780.5600.4240.3330.270C7H8O o-Cresol 3.035 1.5620.961C7H8O m-Cresol12.9 4.417 2.093 1.207C7H8O Benzyl alcohol 5.474 2.760 1.618 1.055C7H8O Anisole 1.0560.7470.5540.427C7H9N N-Methylaniline 4.120 2.042 1.2220.8250.606C7H9N o-Methyl aniline10.3 3.823 1.936 1.1980.839C7H9N m-Methyl aniline8.180 3.306 1.679 1.0140.699C7H9N Benzylamine 1.624 1.0800.7690.577C7H14Methylcyclohexane0.9910.6790.5010.3900.316C7H141-Heptene0.4410.3400.2730.226C7H14O2-Heptanone0.7140.4070.297C7H14O2Heptanoic acid 3.840 2.282 1.488 1.041C7H16Heptane0.7570.5230.3870.3010.243C7H163-Methylhexane0.350C7H16O1-Heptanol 5.810 2.603 1.3890.849C7H16O2-Heptanol 3.955 1.7990.9870.615C7H16O3-Heptanol 1.9570.9760.584C7H16O4-Heptanol 4.207 1.6950.8820.539C7H17N Heptylamine 1.3140.8650.6000.434C8H8Styrene 1.0500.6950.5070.3900.310C8H8O Acetophenone 1.6810.634C8H8O2Methyl benzoate 1.857C8H8O3Methyl salicylate 1.1020.815C8H10Ethylbenzene0.8720.6310.4820.3800.304C8H10o-Xylene 1.0840.7600.5610.4320.345C8H10m-Xylene0.7950.5810.4450.3530.289C8H10p-Xylene0.6030.4570.3590.290C8H10O Phenetole 1.1970.8170.5940.453C8H11N N,N-Dimethylaniline 1.996 1.3000.9110.6750.523C8H11N N-Ethylaniline 3.981 2.047 1.2310.8250.596C8H16Ethylcyclohexane 1.1390.7840.579C8H16O2Octanoic acid 5.020 2.656 1.654 1.147C8H18Octane0.7000.5080.3850.3020.243C8H18O1-Octanol7.288 3.232 1.6810.991C8H18O4-Methyl-3-heptanol 1.904 1.0850.7020.4970.375C8H18O5-Methyl-3-heptanol 2.052 1.1780.7620.5360.401C8H18O2-Ethyl-1-hexanol20.7 6.271 2.631 1.3600.810C8H18O Dibutyl ether 1.4170.9180.6370.4660.3560.281C8H19N Dibutylamine 1.5090.9180.6190.4490.345C8H19N Diisobutylamine 1.1150.7230.5110.3840.303C9H7N Quinoline 3.337 1.892 1.2010.833C9H10Indane 2.230 1.3570.9310.6920.545C9H12Cumene 1.0750.7370.5476-178 Viscosity of LiquidsMolecularformula NameViscosity in mPa s–25°C0°C25°C50°C75°C100°CC9H14O Isophorone 4.201 2.329 1.4150.9230.638C9H18O5-Nonanone 1.1990.8340.6190.484C9H18O2Nonanoic acid7.011 3.712 2.234 1.475C9H20Nonane0.9640.6650.4880.3750.300C9H20O1-Nonanol9.123 4.032C10H10O4Dimethyl phthalate63.214.4 5.309 2.824 1.980C10H14Butylbenzene0.9500.6830.515C10H18cis-Decahydronaphthalene12.8 5.645 3.042 1.875 1.2710.924C10H18trans-Decahydronaphthalene 6.192 3.243 1.948 1.2890.9170.689C10H20O2Decanoic acid 4.327 2.651C10H22Decane 2.188 1.2770.8380.5980.4530.359C10H22O1-Decanol10.9 4.590C11H24Undecane 1.707 1.0980.7630.5620.433C12H10O Diphenyl ether 2.130 1.407 1.023C12H26Dodecane 2.277 1.3830.9300.6730.514C13H12Diphenylmethane 1.2650.929C13H28Tridecane 2.909 1.724 1.1290.7960.594C14H30Tetradecane 2.128 1.3760.9530.697C16H22O4Dibutyl phthalate48366.416.6 6.470 3.495 2.425C16H34Hexadecane 3.032 1.879 1.2600.899C18H38Octadecane 2.487 1.609 1.132 Viscosity of Liquids 6-179。

合集下载

USP 911 VISCOSITY (粘度)

USP 911 VISCOSITY (粘度)

911VISCOSITYViscosity is a property of liquids that is closely related to the resistance to flow. It is defined in terms of the force required to move one plane surface continuously past another under specified steady-state conditions when the space between is filled by the liquid in question. It is defined as the shear stress divided by the rate of shear strain. The basic unit is the poise; however, viscosities commonly encountered represent fractions of the poise, so that the centipoise (1 poise = 100 centipoises) proves to be the more convenient unit. The specifying of temperature is important because viscosity changes with temperature; in general, viscosity decreases as temperature is raised. While on the absolute scale viscosity is measured in poises or centipoises, for convenience the kinematic scale, in which the units are stokes and centistokes (1 stoke = 100 centistokes) commonly is used. To obtain the kinematic viscosity from the absolute viscosity, the latter is divided by the density of the liquid at the same temperature, i.e., kinematic viscosity = (absolute viscosity)/(density). The sizes of the units are such that viscosities in the ordinary ranges are conveniently expressed in centistokes. The approximate viscosity in centistokes at room temperature of ether is 0.2; of water, 1; of kerosene, 2.5; of mineral oil, 20 to 70; and of honey, 10,000.Absolute viscosity can be measured directly if accurate dimensions of the measuring instruments are known, but it is more common practice to calibrate the instrument with a liquid of known viscosity and to determine the viscosity of the unknown fluid by comparison with that of the known.Many substances, such as the gums employed in pharmacy, have variable viscosity, and most of them are less resistant to flow at higher flow rates. In such cases, a given set of conditions is selected for measurement, and the measurement obtained is considered to be an apparent viscosity. Since a change in the conditions of measurement would yield a different value for theapparent viscosity of such substances, the instrument dimensions and conditions for measurement must be closely adhered to by the operator.Measurement of Viscosity— The usual method for measurement of viscosity involves the determination of the time required for a given volume of liquid to flow through a capillary. Many capillary-tube viscosimeters have been devised, but Ostwald and Ubbelohde viscosimeters are among the most frequently used. Several types are described, with directions for their use, by the American Society for Testing and Materials (ASTM, D-445). The viscosity of oils is expressed on arbitrary scales that vary from one country to another, there being several corresponding instruments. The most widely used are the Redwood No. I and No. II, the Engler, the Saybolt Universal, and the Saybolt Furol. Each of these instruments uses arbitrary units that bear the name of the instrument. Standard temperatures are adopted as a matter of convenience with these instruments. For the Saybolt instruments, measurements usually are made at 100F and 210F; Redwood instruments may be used at several temperatures up to 250F; and values obtained on the Engler instrument usually are reported at 20C and 50C. A particularly convenient and rapid type of instrument is a rotational viscosimeter, which utilizes a bob or spindle immersed in the test specimen and measures the resistance to movement of the rotating part. Different spindles are available for given viscosity ranges, and several rotational speeds generally are available. Other rotational instruments may have a stationary bob and a rotating cup. The Brookfield, Rotouisco, and Stormer viscosimeters are examples of rotating-bob instruments, and the MacMichael is an example of the rotating-cup instrument. Numerous other rotational instruments of advanced design with special devices for reading or recording, and with wide ranges of rotational speed, have been devised.Where only a particular type of instrument is suitable, the individual monograph so indicates.For measurement of viscosity or apparent viscosity, the temperature of the substance being measured must be accurately controlled, since small temperature changes may lead to marked changes in viscosity. For usual pharmaceutical purposes, the temperature should be held to within ±0.1.Procedure for Cellulose Derivatives— Measurement of the viscosity of solutions of the high-viscosity types of methylcellulose is a special case, since they are too viscous for the commonly available viscosimeters. The Ubbelohde viscosimeter may be adapted (cf. ASTM, D-1347) to the measurement of the ranges of viscosity encountered in methylcellulose solutions.Calibration of Capillary-Type Viscosimeters— Determine the viscosimeter constant, k, for each viscosimeter by the use of an oil of known viscosity.* Ostwald-Type Viscosimeter—Fill the tube with the exact amount of oil (adjusted to 20.0 ± 0.1) as specified by the manufacturer. Adjust the meniscus of the column of liquid in the capillary tube to the level of the top graduation line with the aid of either pressure or suction. Open both the filling and capillary tubes in order to permit the liquid to flow into the reservoir against atmospheric pressure. [ NOTE—Failure to open either of these tubes will yield false values. ] Record the time, in seconds, for liquid to flow from the upper mark to the lower mark in the capillary tube.Ubbelohde-Type Viscosimeter—Place a quantity of the oil (adjusted to 20.0 ±0.1) in the filling tube, and transfer to the capillary tube by gentle suction, taking care to prevent bubble formation in the liquid by keeping the air vent tube closed. Adjust the meniscus of the column of liquid in the capillary tube to the level of the top graduation line. Open both the vent and capillary tubes in order to permit the liquid to flow into the reservoir against atmosphericpressure. [ NOTE—Failure to open the vent tube before releasing the capillary tube will yield false values. ] Record the time, in seconds, for the liquid to flow from the upper mark to the lower mark in the capillary tube.Calculations—Calculate the viscosimeter constant, k, from the equation:k = v / d t,in which v is the known viscosity of the liquid in centipoises, d is the specific gravity of the liquid tested at 20/20, and t is the time in seconds for the liquid to pass from the upper mark to the lower mark.If a viscosimeter is repaired, it must be recalibrated, since even minor repairs frequently cause significant changes in the value of its constant, k.*Oils of known viscosities may be obtained from the Cannon Instrument Co., Box 16, State College, PA 16801. For methylcellulose, choose an oil the viscosity of which is as close as possible to that of the type of methylcellulose to be determined.Auxiliary Information—Staff Liaison : Catherine Sheehan, B.Sc., Scientist Expert Committee : (EGC05) Excipient General ChaptersUSP29–NF24 Page 2785Phone Number : 1-301-816-8262。

viscosity水的黏度-英文释义

viscosity水的黏度-英文释义

Kinematic viscosity is a property of liquids and gases that represents how easily a given substance can flow. In practical terms, it is closely related to how thick the substance is. Both absolute and kinematic viscosity change according to temperature.To obtain kinematic viscosity, the absolute viscosity of a substance is divided by its density. Kinematic viscosity is represented by the Greek letter nu, which resembles a "v;" absolute viscosity is represented by mu, which resembles a "u;" and density is represented by rho, which resembles a "p." The equation, therefore, is v = u/p.、Absolute viscosity, also called dynamic viscosity, measures a substance's resistance to flow. It is determined experimentally by sandwiching a liquid or gas between two plates and applying a known amount of pressure to move the top plate — the dynamic viscosity depends on the pressure, the amount of time it was applied, and the distance the plate moved in that time. Dynamic or absolute viscosity is based on the International System of Units (SI) units of pascal-seconds (Pa*s), which means that if a pressure of 1 Pa is applied for 1 second, the plate will move the same distance as the distance between the two plates. Centipoise (cP) is also a common unit for dynamic viscosity — 1 cP is the viscosity of water around room temperature. The imperial units, pound-seconds per square foot (lb*s/ft^2), are very seldom usedWhat is the diffirence between kinematic viscosity and dynamic viscosity?The viscosity of a liquid is an important physical property that affects the behavior of the liquid as it flows. Highly viscous liquids are more resistant to deformation by stress and flow less easily, while less viscous liquids flow more easily and are less stress-resistant. The two main ways to measure viscosity are in terms of dynamic and kinematic viscosity. These measures are interrelated, but have different applications.Dynamic viscosity, also called absolute viscosity, is the more commonly used measurement. It measures the resistance of a fluid to flow — in other words, the internal friction of the fluid, or how easily it can deform under mechanical stress at a given temperature and pressure. The technical definition of dynamic viscosity is the ratio of shear stress to velocity gradient. When force is applied perpendicular to the surface of a liquid, it deforms sideways, or shears. The ease or difficulty of this deformation is the dynamic viscosity, sometimes referred to simply as viscosity.Kinematic viscosity, by contrast, measures the resistance of the liquid to flow in the presence of gravity. This measure is obtained by taking the liquid’s dynamic viscosity and dividing it by the liquid’s density. The higher the viscosi ty of the liquid, the less easily it will flow under the force of gravity and the higher its kinematic viscosity will be.Dynamic and kinematic viscosity are expressed in different units of measurement. The International System of Units (SI) measurement units for dynamic viscosity are pascal-seconds. Pascals are a measurement of pressure — in this case, the shear stress applied to the liquid —while seconds measure the time it takes to deform. Dynamic viscosity can also be measured with a unit called the poise, another measure relating pressure versus time. The common unit used to measure kinematic viscosity is the stokes,or square centimeters per second, although sometimes the SI unit of square meters per second is used.The use of dynamic and kinematic viscosity measurements is essential for various real-world applications. For example, it is important to formulate paint with a certain dynamic viscosity to ensure that it can be mixed and applied in the correct thickness. The measurement of kinematic viscosity is used more often in cases where a fluid must flow through a pipe or lubricate machinery, as in a car engine.Products such as motor oil that are subjected to varying physical conditions must have a specific dynamic and kinematic viscosity to behave correctly. The viscosity of fluids changes based on temperature and pressure. For example, in cold weather oil thickens and becomes denser, causing it to flow less easily. It is important to know both the dynamic and kinematic viscosity ratios in this situation to predict how the oil will behave at different temperatures.。

NDJ-5S旋转粘度计英文说明书(全英文)

NDJ-5S旋转粘度计英文说明书(全英文)


speed.
x. This instrument has overload alarm function, if the measured value bigger
than 100%, measured value will be displayed “over”. In order to ensure
NDJ-5S Digital rotary viscometer is used for determining the liquid viscose
capacity and the absolute viscosity. Comparing with other similar products, this
instrument has the following features:
High measuring accuracy;
Stable in measured display;
Easy operation and read-out;
Excellent in Anti- interference.
operation manual carefully before you use.
2) This instrument should be used under the designed voltage and frequency and
their allowable error ranges, or incorrect results could be resulted.
NDJ-5S has been widely used to determine and measure the liquid viscosity in
超临界萃取技术英文版(双语)

超临界萃取技术英文版(双语)

Everybody knows the three physical states: solid, liquid and gas. But a fourth one exists. By controlling temperature and pressure every pure substance can be set into a supercritical state .
Viscosity (cP) 0.01 0.05-0.1
Diffusivity (mm2 /s) 1-10 0.01-0.1
Liquid
1000
0.5-1.0
0.001
Features (advantages & defects ) of SCFE
advantages
1.SF combines desirable properties of gases and liquids
Supercritical fluid extraction:
SCF as extractant. It also is called as: Pressure fluid extraction; Supercritical gas extraction; Critical solvent extraction.
The extraction technology employing
The basic principle of SCFE
The basic principle of SFE is as followings: 1.when the feed material is contacted with a supercritical fluid, the volatile substances will partition into the supercritical phase。 物料与超临界流体接触，挥发性成分被萃取进入超临界流体 2.After the dissolution of soluble material the supercritical fluid containing the dissolved substances is removed from the feed material. 可溶性物质被溶解之后，超临界流体转移到另外一个罐中； 3.The extracted component is then completely separated from the SCF by means of a temperature and/or pressure change. 通过调整压力或温度，超临界流体密度下降，目标成分与流体完全分离析出 4.The SCF is then may be recompressed to the extraction conditions and recycled. 流体重新被压缩变回超临界状态，再次进入萃取体系。