Capillary Viscometer Research Articles

Densities and Viscosities of Oleic Acid at Atmospheric Pressure

AbstractThe densities of oleic acid were measured over the temperature range from (293 to 459) K at atmospheric pressure using a densimeter based on the modified hydrostatic weighing method. The dynamic viscosities of the same oleic acid sample were measured using a capillary viscometer (VPZ‐2 m) in the range from (293 to 363) K at atmospheric pressure. The combined expanded uncertainty of the density, atmospheric pressure, viscosity, and temperature measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.15%, 1.0%, 3.5%, and 15 mK, respectively. The values of uncertainty for density and viscosity include the effects of purity and calibration (total expanded uncertainty). These experimental data were used to develop wide‐range correlations for the density and viscosity based on theoretically confirmed Arrhenius–Andrade and Vogel‐Tamman‐Fulcher (VTF) models. The value of the glass temperature ( T g=179.78 K.) for the oleic acid was estimated using the VTF parameters derived from the present viscosity measurements. To additionally validate the reliability of the measured density data, the same oleic acid samples were measured using the pycnometric method. The present study showed that the densities measured using the modified hydrostatic weighing densimeter (HWD) agree with the values obtained using the pycnometric method within 0.09% for Sample 1 and 0.25% for Sample 2.

Density and viscosity of binary mixtures of diethyl oxalate with ethanol, ethyl acetate, tetrahydrofuran, and toluene

ABSTRACT This study presents the densities and viscosities of four binary liquid mixtures containing diethyl oxalate (DEO) with the organic solvents ethanol, ethyl acetate (EA), tetrahydrofuran (THF), and toluene at temperatures ranging from 303.15 to 323.15 K and at atmospheric pressure. DEO is widely used in the pharmaceutical industry as an intermediate or reaction reagent for synthesizing active pharmaceutical ingredients. The measured thermophysical properties are important for pharmaceutical process design and development. A vibrating tube digital density meter and a capillary viscometer were used for density and viscosity measurements, respectively. According to the measurement data, the excess molar volumes (VE ) and viscosity deviations ( ) of the binary mixtures were calculated and satisfactorily correlated with the four-parameter Redlich–Kister equation. Ethanol or THF addition to DEO led to a positive deviation of VE , whereas EA or toluene addition to DEO led to a negative deviation. These results indicated the molecular packing of DEO with EA and toluene was more efficient than that with ethanol and THF. By contrast, the values of the four binary mixtures were negative, indicating that the viscosity was markedly lower than that of an ideal mixture.

Fatty Acids of Enteromorpha intestinalis Emulsified Drug Delivery Nanoemulsion: Evaluation of Loading Mechanism and Release Kinetics for Drug Delivery

The selection of bio-surfactants in consonance with the pharmaceutical drug in the preparation of nanoemulsion for the controlled release of drugs and bio-compatibility is still a scientific moot. We have investigated the possible mechanism of drug-surfactant interaction in this research that can iron out the surfactant identification complication. The bio-surfactants 9-Octadecenoic acid, 9-Octadeceamide and Isopropyl Myristate isolated from a marine weed Enteromorpha intestinalis were used together to stabilize the nanoemulsion. The encapsulation efficiency and release kinetics of Aspirin in nanoemulsion under different pH conditions from the nanoemulsion was studied. Nanoemulsion was prepared by the ultrasonication method and characterized by centrifugation, capillary viscometer, freeze–thaw cycle assays, dynamic light scattering analysis (DLS) and HR-TEM. The mechanism of drug surfactant interaction deduced using Spectrophotometric and ATR-FTIR analysis revealed the possible bond formations. In-vitro drug release profiles of aspirin (model drug) were evaluated by dialysis in different pH (1.2, 6.8 and 7.4) using by UV-spectrophotometry and the effective release of aspirin was observed in pH 6.8. The release kinetics was studied to identify the mode of release. The bio-surfactant based nanoemulsion of 15:6:9 composition exhibited ideal stability and controlled release in all pH conditions with linearity and time-dependent paradigm.

Dissipative method of research of high-viscosity media rheological properties

The rheological properties research of highly viscous fluid is attractive from both practical and scientific points of view. The research is necessary in the calculation of energy cost of production, equipment, and in the research of their structure of media and flow rules. In general, the rheological properties research of highly viscous fluids, which demonstrate non-Newtonian fluid properties, are carried out on the rotation and capillary viscometers. However, it is rather difficult to use the data obtained in this way in the technical calculations of the equipment. The reason is the difference in hydrodynamic conditions on which the viscosity of non-Newtonian fluids depends. A method for studying the rheological properties of highly viscous fluid is considered based on on the conversion of friction mechanical energy to the heat energy during agitation. The necessity of using the proposed method in rheological studies of highly viscous media has been substantiated. Theoretical explanation of the physical essence of the method is presented and the equation for viscosity calculation is derived. An experimental verification of the suggested method was carried out using the example of determining the viscosity of glycerin aqueous solution at 95 % concentration; the obtained data are compared with known results from the literature. The discrepancy between the experimental and calculated values of the power criterion was no more than 14 %.

An application of thickener to increase viscosity of liquid CO2 and the assessment of the reservoir geological damage and CO2 utilization

ABSTRACTIn comparison to hydraulic fracturing, CO2 fracturing technology is more efficient and effective in solving environmental problems caused by the fracturing process. However, the low viscosity caused by pure CO2 under high pressure hinders the development of the entire fracturing technology. Given that, a siloxane that can significantly improve the liquid CO2 viscosity is prepared and the excellent performance to thicken CO2 by silicone polymer is shown. Polymerization that occurs under water conditions presents a trend and is more likely to trigger reaction than ring-opening polymerization under anhydrous conditions. The thickening performance test is conducted by capillary viscometer self-designed at 35°C and 10 MPa. Moreover, a rising trend in viscosity is demonstrated with increase in thickener concentration. Smaller damages and chemical residue exists in the stratum after CO2 fracturing. In addition, there are no changes that occur in the quality of crude oil. A fine conclusion for thickening performance provides a basis for the synthesis of the polymer to thicken CO2.

Blood viscosity of individuals with alcohol abuse

Abstract Aim: Alcohol abuse is accepted as a serious public health problem worldwide, and is a well-known cause of systemic alterations in the organism. The aim of our study is to investigate whether heavy alcohol consumption results in increased blood viscosity in men. We compared the levels of blood viscosity with the age-matched healthy male volunteers. Material and Methods: In order to study the blood rheology of alcohol abusers, we measured blood viscosity in 20 male patients prior to the detoxification treatment. Blood viscosity measurement was performed using Harkness Capillary viscometer. Results: Comparison of blood viscosity yielded a statistically significant elevation (p

WALL SLIPPAGE IN HIGH-PRESSURE CAPILLARY VISCOMETRY: EFFECTS OF MOLECULAR WEIGHT, COMPOUND COMPOSITION, AND CAPILLARY SURFACE COATING

ABSTRACT Flow behavior is of major importance in the extrusion processing of rubber compounds. It is evaluated by means of a series of tests on a high-pressure capillary viscometer (HCV). Adhesion between the polymer melt and the capillary wall is assumed in all current calculation models, although such adhesion does not always pertain to the case of rubber compounds. To date, no uniform model discussed in the literature on the topic extensively describes the wall slippage behavior of rubber compounds. The phenomenon of wall slippage is analyzed by determining the power-law parameters n (flow exponent) and K (consistency factor) from the flow curve in the subcritical flow range. This makes it possible to explicitly calculate first the slip velocity and then the slippage ratio relative to the total volume flow as a function of the given shear rate and temperature. The work is based on the testing of EPDM raw polymers of different molecular weights in the HCV. In addition, EPDM compounds containing either a carbon black or a softener were analyzed with regard to their flow behavior. The rheological analysis was carried out on three variously coated flow channels. It was observed that with attainment of a critical wall shear stress, the wall slippage effect becomes more pronounced; thus, occurrences of flow anomalies such as slip-stick or shark-skin significantly influence processing and flow behavior. Wall slippage effects are noticeable, however, even before the critical wall shear stress is attained.

On-line rheological characterization of semi-solid formulations

The rheological profile of a semi-solid product is a critical quality attribute. To monitor changes of this attribute during manufacturing, it would be beneficial to measure the rheological parameters in an on-line or in-line mode and implement this as a part of a control strategy for manufacturing of semi-solids. None of the process analytical technology (PAT) tools for measuring the rheological parameters have yet been widely accepted in the pharmaceutical area, as most of the equipment can only measure viscosity. Therefore, an automated system based on the measurement of pressure difference across both a topology optimized channel and a tube geometry (capillary viscometer) was investigated. The Pressure Difference Apparatus (PDA) can sample from the bulk intermediate/product stream and press the sample through the apparatus at different flow rates to yield a frequency sweep (G′ and G″) and a flow curve (viscosity). A calibration model was successfully prepared and verified with hydroxyethyl cellulose gels with polymer content varying from 1.0 to 1.5% (w/w) resulting in gels of different viscosities. The calibration model was used on-line during manufacturing of a gel and manufacturing changes related to dilution of the product were clearly reflected in the batch evolution profiles. The measurements with the PDA reflected the shear rate and frequency ranges relevant for manufacturing and thereby complemented the rheology measurements obtained with a standard rheometer with real time data.

On the interpretation of shear viscosity ultrasonic measurements

This article discusses the possibility of using the measurements of ultrasonic wave parameters to estimate numerical values of shear and bulk viscosities on-line. It is noted that to increase the reliability of such estimates, it is necessary to introduce classification criteria for liquids. The on-line classification of liquids can be carried out through the measurement and comparison of the real and imaginary parts of liquid acoustic shear impedances. When the measured real and imaginary parts of the impedance are equal, the calculated ultrasonic viscosity values do not differ from the shear viscosity measured by a capillary viscometer. This occurs in liquids with a shear viscosities of less than 0.015 … 0.02 Pa ∗ s (i.e., low-viscous liquids). If the real and imaginary components of the liquid shear impedance are not equal, however, the proportionality coefficient between the viscous tensor and the shear strain rate becomes a complex number, and the calculated shear viscosity values are significantly different from values obtained by the capillary viscometer. This holds true in viscous liquids. The interpretation of the results in viscous non-polymeric liquids is considered in detail within the framework of the Maxwell model, and also within the framework of a proposed shear viscosity relaxation model. The influence of the relaxation process on the measured values of ultrasonic shear viscosity is considered. As an example, the model takes into account the presence of small molecular clusters in viscous liquids. The propagating viscous wave breaks the equilibrium distribution of the clusters, which in turn causes the relaxation process.It is shown that the shear viscosity of such liquids calculated from the ultrasonic data becomes a complex quantity depending on the frequency. A scheme for bulk viscosity measurements in the on-line mode is proposed. To find numerical values of the bulk viscosity, it is necessary to measure the real and imaginary components of the liquid shear impedance and the absorption coefficient of the longitudinal waves (if the thermal conductivity contribution can otherwise be neglected). Then the Stokes sound absorption coefficient and, accordingly, the numerical value of the bulk viscosity coefficient can be calculated.

ПОЛІМЕР-ПОЛІМЕРНИЙ КОМПОЗИТ ОТРИМАНИЙ ШЛЯХОМ ПЕРЕРОБКИ ВІДХОДІВ ПВХ ЛІНОЛЕУМУ

Development of technology for the processing of mixed waste of vinyl flooring by their joint milling and plasticization. The determination of the MFI was carried out according to ISO 1133: 1997 on a capillary viscometer with a constant pressure and temperature (190 ± 0.5) ° C and a weight of 2.16 kg. The thermostability and melting temperature were determined on the Hipro RM 200C plastograph. Mechanical properties were determined on a breaking machine according to ASTM D638. Hardness - using a Shore D durometer, hydrostatic weighing density on an analytical balance RADWAG AS-X2. Equipment for milling and plasticization of a mixture of PVC / PET waste was selected. Qualitative milling of mixed waste is achieved by using a low speed rotary knife grinder with rotor speed of 300 rpm. The properties of the reinforced PVC were obtained. The strength of this film compared with the classic recipe is lower but when by using such materials in the composition it is possible to obtain a material with high physical and mechanical properties and achieve maximum non-waste production which will also have a positive effect on the economy of the enterprise. The technology for joint processing of mixed vinyl flooring waste was developed for the first time. The features of reinforcing PVC matrix with fibers of a PET was obtained at the receipt of films from mixed vinyl flooring waste. The developed technology allows to provide non-waste production of vinyl flooring at enterprises.

ДОСЛІДЖЕННЯ ОСОБЛИВОСТЕЙ ПРИСКОРЕНОГО РОЗКЛАДУ ВТОРИННИХ ПОЛІОЛЕФІНІВ

Investigation of the features and conditions of accelerated degradation of films based on PE wastes to create and develop an efficient technology for the utilization of flexible polyolefin packaging. The chemical composition of the inorganic residue after the burning of polymers wastes was determined by X-ray fluorescence method. The determination of the MFI of PE was carried out in accordance with ISO 1133: 1997 on a capillary viscometer of constant pressure at a temperature (190 ± 0.5) °С and a weight of 2,16 kg. Deformation-strength properties - according to ASTM D638. Ash content - according to ISO 3451-2: 1998 «Plastics. Determination of ash content». The ability to accelerate the degradation of polyolefine wastes in an environment was established. The changes of mechanical properties of PE films of different composition in conditions of artificial aging were investigated. The ability of calcium carbonate to exhibit the effect of oxide additives in PE films during the aging process was revealed. The features of accelerated degradation of polyolefine wastes in artificial aging conditions were first discovered and investigated. Obtained initial data for the production of PE film technology based on polyolefine wastes, then capable of accelerated degradation under environmental conditions

Increased plasma viscosity in plasma cell dyscrasia and whole blood viscosity in polycythemia vera.

Although hyperviscosity syndrome in plasma cell dyscrasia (PCD) and thrombosis in myeloproliferative neoplasm (MPN) are major causes of morbidity and mortality, blood viscosity measurements are often underutilized. This study aimed to characterize whether whole blood viscosity (WBV) or plasma viscosity (PV) could be predictive of hyperviscosity syndrome in PCD and could be elevated in subgroups of MPN. A total of 75 patients with hematologic diseases: PCD (n = 26), MPN (n = 25) including polycythemia vera (P. vera) and lymphoma (n = 24) were enrolled along with 104 healthy controls. Both WBV and PV were measured using a capillary tube viscometer. Hyperviscosity syndrome was defined as having 2 or more hyperviscosity symptoms. Patients with PCD showed significantly higher PVs at high and low shear rates when compared to healthy controls, especially in those with hyperviscosity syndrome. The sensitivity and specificity of WBV and PV in detecting hyperviscosity syndrome were 28.6% and 94.1%, and 71.4% and 66.7%, respectively. Patients with P. vera exhibited high WBV and RBC counts compared to healthy controls. PV is predictive of hyperviscosity syndrome in PCD and WBV is elevated in patients with P. vera. It suggests that hemorheologic disturbances exist in patients with PCD and MPN and that tests of viscosity may be helpful in detecting hemorheological disturbances.

Rheological properties of surface-modified nanoparticles-stabilized CO2 foam

This study investigates the rheological properties of surface-modified nanoparticles-stabilized CO2 foam in porous media for enhanced oil recovery (EOR) applications. Due to the foam pseudo-plastic behavior, the foam apparent viscosity was estimated based on the power law constitutive model. The results show that foam exhibit shear-thinning behavior. The presence of surface-modified silica nanoparticles enhanced the foam bulk apparent viscosity by 15%. Foam apparent viscosity in the capillary porous media was four times higher than that in capillary viscometer, and foam apparent viscosity increased as porous media permeability increases. The high apparent viscosity of the surface-modified nanoparticles-stabilized foam could result in effective fluid diversion and pore blocking processes and enhance their potential applications in heterogeneous reservoir.

Experimental investigation on the viscosity characteristics of water based SiO2-graphite hybrid nanofluids

The hybrid nanofluids were obtained by dispersing Silicon dioxide and Graphite nanoparticles in distilled water. Viscosity is regarded as internal resistant of a fluid, and it affects the pumping power and the convective heat transfer coefficient. This hybridization requires to be experimentally determined since its properties are unknown. For viable real life applications viscosity and density parameters are significant, owing to their influence on energy and cost saving of heat exchangers by affecting pressure drops. The viscosity measurements of hybrid nanofluids were performed using capillary tube viscometer, within a temperature range of 15 °C to 60 °C at several volume concentrations up to 2%. Furthermore, the volumetric fraction ratios within nano composites have also been changed, since there is more than one nano particle. The highest increment of viscosity was observed to be 36.12% in the nanofluid of 2 vol% at 15 °C. The conclusion was supported with SEM images and a regression correlation was proposed and afterward the results were compared with relevant literature. It is able to estimate the viscosity of hybrid nanofluid with 2.4% accuracy.

Effect of potassium chloride on the solvation behavior of caffeine, theophylline and theobromine: Volumetric, viscometric, calorimetry and spectroscopic approach

The density (ρ), speed of sound (u), viscosity (η) and enthalpy of dilution (q) measurements for methylxanthines (caffeine, theophylline and theobromine) in aqueous medium and in aqueous solutions of (0.10–1.00) mol·kg−1 KCl covering a temperature range T = (288.15–318.15) K and at p = 101.325 kPa have been accomplished using a density and sound velocity meter, Micro-Ubbelohde type capillary viscometer and Isothermal Titration Calorimetry, respectively. Transfer parameters evaluated from the data suggest that competition among various interactions exists at low and high molalities of KCl(aq.) solutions. The increase in bitterness and decrease in hydration number of methylxanthines with the mB values have been observed. The dehydration effect of KCl(aq.) at low molalities on the methylxanthines has also been established using ITC. Positive change in the chemical shifts (1H NMR) and increase in absorption intensity (UV–vis) of methylxanthines in the presence of KCl(aq.) further support our results.

Experimental investigation on rheological property of foamy oil in Venezuela

ABSTRACTSome heavy oil reservoirs present foamy oil flow behavior under primary production, and the foamy oil viscosity and rheological property are important factors that influence the efficiency of the process. The variation of the foamy oil viscosity during the depletion process is complicated due to the generation and migration of dispersed gas bubbles within the oil phase, and still remains as a controversial topic. This study aims to investigate this issue by measuring the foamy oil viscosity at different pressure, temperature and flow rate with a capillary viscometer system equipped with a specially designed foamy oil generator to guarantee the generation and stable flow of gas-in-oil dispersions. Meanwhile, the dead oil and live oil viscosities were also measured for comparison. Based on the results from all the tests the following conclusions can be drawn. Below the bubble point pressure, the dispersed gas-bubble volume fraction and foamy oil viscosity increase with pressure decline; the viscosity of foamy oil is higher than that of live oil, and the gap between them widens with pressure decline. Moreover, foamy oil behaves as shear-thinning power-law fluid, and the shear-thinning effect becomes stronger with the decrease of pressure. The foamy oil rheology is also affected by temperature, and the shear-thinning effect becomes milder with the increase of temperature. Based on the experimental data, a formula was established for estimating foamy oil apparent viscosity within porous media, which took flow rate, shear-thinning flow parameters, permeability, porosity and other factors into consideration.

Densities and Viscosities for Binary Liquid Mixtures of Biodiesel + 1-Pentanol, 2-Pentanol, or 2-Methyl-1-Butanol from (288.15 to 338.15) K at 0.1 MPa

This work presents experimentally determined densities and viscosities of biodiesel blended with 1-pentanol, 2-pentanol, and 2-methyl-1-butanol between 288.15 and 338.15 K at 0.1 MPa. The densities are measured using a vibrating tube densimeter, and the kinematic viscosities, using a glass capillary viscometer. The measured density and viscosity of the pure components agree with values reported in the literature within average absolute percentage deviations of 0.04 and 0.83%, respectively. The excess molar volumes and viscosity deviations show positive and negative deviations from ideality, respectively. The Redlich–Kister equation is used to represent the composition behavior of the excess molar volumes and viscosity deviations. The experimental kinematic viscosities have a minimum value over a composition range of 50–90% alcohol by weight. The McAllister equation correlates the kinematic viscosity within an average absolute percentage deviation of 1.77%, while the Nava-Rios equation correlates the kinem...

Flow Behaviour and Microstructure of a \u03b2-Glucan Concentrate

The extensional viscosity is an important rheological characteristic of polymer melts. It is however not as frequently reported on as the shear viscosity. The extensional viscosity is of special interest when considering polymeric materials for foaming and film blowing processes. Here, the extensional (and shear) viscosity along with the melt strength and the tensile properties of the corresponding solid film of a β-glucan concentrate are reported on. A capillary viscometer equipped with a hyperbolic die, yielding a contraction flow, was used to assess the extensional viscosity of the aqueous β-glucan compound at room temperature and at elevated temperatures (110 and 130 °C). In general, the extensional viscosity as well as the shear viscosity decreased with increasing deformation rate. The influence of two different amounts of added water (40 and 50%) was also examined. As expected, both types of viscosities decreased with increasing temperature. It is suggested that gelatinization of the starch fraction in the concentrate at 110 and 130 °C contributes to temperature dependence of the viscosity. To some extent, this is supported by light microscopy and confocal scanning laser microscopy studies of the microstructure of the materials. The results reported here indicate that the β-glucan concentrate might, after some modifications, be used as a complement to fossil-based polymers and processed by conventional manufacturing techniques.

Viscosity of squalane under carbon dioxide pressure — Comparison of acoustic levitation with conventional methods

Viscosity measurements with CO2-saturated squalane with three different methods, a novel and two classical ones, are compared in a range of pressure from 0.1 MPa to 10.1 MPa at temperatures of 313 K, 333 K and 353 K. The dynamic viscosities were measured using an acoustic levitator developed for measurements under pressure, a capillary viscometer and a rotational viscometer. Squalane is saturated with CO2 at each pressure and temperature measured. It is shown, that the measured data are in good agreement with the values published by Dilchert. With the comparatively fast measurement time, the acoustic levitation has been proven to be a promising method.

A new, heavier-than-water silicone oil: A solution of perfluorohexyloctane in polydimethylsiloxane.

To pre p a re and explore new solutions of semifluorinated alkane in silicone oil, which have a specific gravity slightly higher than silicone oil and vitreous fluid (referred to in the following as heavier-than-water silicone oils (HWSs), and to investigate, in vitro, whether HWSs can be used to plug retina holes, while allowing dehydration of the subretinal space. HWS solutions were pre p a red with silicone oil 5000 and perfluorohexyloctane (F6H8). The stabiliy was investigated under different conditions. The viscosity was determined by means of a capillary viscometer. The surface and interface tension were measured using the ring method. HWSs are insoluble in an aqueous medium. Densiron68 (HWS 1.06) is a transparent homogeneous liquid which is slightly heavier (1.06 g/cm3) than water and has a refractive index close to that of vitreous liquid. Densiron68 (HWS 1.06) has a low viscosity (1480 mPas) and interface tension (40.82 mN/m), making it an effective tamponade in the surgical treatment of an inferior detached retina. In addition, the interfaces between Densiron68 and other perfluorocarbon liquids are clearly visible. However, the interface layer between Densiron68 and water is not clear. Finally, all HWSs are stable over the long term at ambient temperatures, as well as physically and thermally resistant. Due to its physiochemical properties, Densiron68 could meet the requirements for a heavier-than-water tamponade. (Eur J Ophthalmol 2005; 15: 627-37).