Measurement Of Liquid Viscosity Research Articles

Quality of care issues for dysphagia: modifications involving oral fluids

This study examined practices of health care providers who thicken oral fluids for patients with impaired swallowing (dysphagia). It contrasts viscosity (thickness) of nectar-like and honey-thick consistencies prepared and measured in a laboratory setting to actual practices in health care settings and to guidelines of the National Dysphagia Diet. The care plans for many patients include changes to fluid thickness to maintain safe intake of oral fluids. Serving patients improperly prepared beverages may contribute to medical complications such as dehydration if patients consume less fluid, or aspiration of overly thin or thickened liquids, which may increase the risk of pneumonia. Descriptive analysis of group trends for viscosity measurements of liquids prepared by health care providers in four care settings to laboratory measurements and the National Dysphagia Diet. Forty-two health care providers participated. Each prepared thickened samples in their natural work environment using typical procedures. Viscosity measurements of modified liquids prepared by health care providers did not compare favourably to published findings of laboratory viscosity measures or to the ranges of the National Dysphagia Diet. Participants who prepared overly thick or overly thin nectar-like liquids followed a similar pattern with honey-like samples. Many participants failed to use product label information in sample preparation. Results suggest that many patients are served modified liquids that are too thick or too thin in relation to their target level of thickness, possibly increasing risk of further medical complications for those who consume them. Product directions that are too vague or general also may contribute to inaccurate results. The patient's nursing staff typically oversees nutritional care plans that may include modifications to oral fluids to enable their patients to safely drink by mouth. Additional consideration should be given to training procedures and possible noncompliance with preparation guidelines.

Physicochemical properties of blue fluorescent protein determined via molecular dynamics simulation

Blue fluorescent protein (BFP) is a mutant of green fluorescent protein (GFP), where the chromophore has been modified to shift the emitted fluorescence into the blue spectral region. In this study, MD calculations were performed with the GROMACS simulation package and AMBER force field to investigate the dependence of BFPs physicochemical properties on temperature and applied pressure. The MD approach enabled us to calculate the compressibility of protein itself, separately from the nontrivial contribution of the hydration shell, which is difficult to achieve experimentally. The computed compressibility of BFP (3.94 x10(-5) MPa(-1)) is in agreement with experimental values of globular proteins. The center-of-mass diffusion coefficient of BFP and its dependence on temperature and pressure, which plays an important role in its application as a probe for intracellular liquid viscosity measurement, was calculated and found to be in good agreement with photobleaching recovery experimental data. We have shown that decreased temperature as well as applied pressure increases the water viscosity, but the concomitant decrease of the BFP diffusion coefficient behaves differently from Stokes-Einstein formula. It is shown that the number of hydrogen bonds around the protein grows with pressure, which explains the aforementioned deviation. Pressure also reduces root mean square (RMS) fluctuations, especially those of the most flexible residues situated in the loops. The analysis of the RMS fluctuations of the backbone Calpha atoms also reveals that the most rigid part of BFP is the center of the beta-barrel, in accord with temperature B factors obtained from the Protein Data Bank.

A New Method for Liquid Viscosity Measurements: Inclined-Tube Viscometry

In this article, a method which can be used to measure the viscosity of liquids with an inclined tube at high pressures and for low-boiling substances is described. The measurement equation was established. The measuring methods for two unknown parameters which are in the measurement equation are presented, and a viscosity measurement system was designed and constructed, which consists of an experimental cell, an inclination-angle control subsystem, a constant temperature subsystem, and a data collection and process subsystem. At atmospheric pressure, the kinematic viscosity of pure water was measured at temperatures from 273.15 K to 333.15 K to demonstrate the performance of the apparatus. The results show that the absolute average relative deviation is 0.84% in comparison with reliable literature values. The kinematic viscosity of saturated liquid R134a and R600a were also measured at temperatures from 273.15 K to 295.15 K and 273.15 K to 300.15 K, respectively, and the corresponding absolute average relative deviations are 1.04% and 1.02% in comparison with reliable literature values. These experimental results demonstrate the performance of the apparatus, while providing estimates of the uncertainty and reliability of the experimental system.

COOMET.M.V-K1 key intercomparison of liquid viscosity measurements

This article describes the results of the first COOMET key comparison in which four national metrology institutes (NMIs) took part. Three samples of Newtonian liquids with nominal kinematic viscosities of 30 mm2/s, 100 mm2/s and 1000 mm2/s at 20 °C were used to determine the degrees of equivalence of the national standards of Belarus, Ukraine and Bulgaria to the standards of NMIs that took part in the KC CIPM (CCM.V-K1).The results of the evaluation of data obtained for all liquids used in the comparison were compared with the reference values (KCRV), obtained in the first key comparison CIPM (CCM.V-K1).Main text.To reach the main text of this Paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

A novel technique for the measurement of liquid viscosity

A novel technique for the measurement of liquid viscosity is presented. In this technique, a disk was driven by a constant speed dc shunt motor in the test liquid. The change in the motor current measured the viscosity. The change in motor current was measured using an instrumentation amplifier and the viscosity of the liquid was measured in terms of output voltage. The temperature of the liquid was controlled using a peltier cooler/heater and was measured using an AD590 two-terminal integrated circuit temperature sensor. The viscosity of vegetable oils (groundnut, palm, sunflower, coconut) in the temperature range from 20 °C to 60 °C were determined. The results thus found were similar to the results obtained from a Redwood viscometer. This technique is useful to measure viscosity of liquids.

Surface tension and viscosity measurements of liquids with the survismeter: a single instrumental unit

Surface tension (γ) and viscosity (η) data of aqueous solutions of the deoxyadenosine (DOA) and the deoxyribose (DOR) sugars have been measured with the survismeter, a new instrument, along with tetrahydrofuran (THF), dimethylformamide (DMF), acetonitrile and dimethylsulphoxide (DMSO) solvents. The same properties have also been measured with a stalagmometer and a viscosimeter, respectively, which afford the same information, albeit at the expense of a larger amount of chemicals and solvents. We obtain comparatively better accuracy in both kinds of measurements than with conventional methods. Therefore, the survismeter lends itself as a simple and reliable instrument.

Survismeter — Type I and II for surface tension, viscosity measurements of liquids for academic, and research and development studies

For centuries surface tension ( γ) and viscosity ( η) data have been measured with individual instruments consuming much time and materials. Thus the two different types of survismeters have been designed and made of borosil glass material for surface tension and viscosity data to rationalize frictional and cohesive forces, respectively. Friccohesity ( σ (s m − 1 , second per meter)) is derived from Fric of frictional and cohesity of cohesive forces of the liquid respectively, and denoted by rational coefficient a η/ γ ( σ). The values of the friccohesity are correlated to the dipole moment of liquids and their plot gives a standard calibration curve along with an equation of the curve with definite values of the coefficients, the friccohesity values are put on the calibration curve to retrieve the dipole moment values. Here, the σ values for each of dimethylformamide, dimethylsulfoxide and acetronitrile solvents along with their 0.05, 0.10 and 0.20 mol kg − 1 aqueous solutions, respectively, were determined at 293.15 K and plotted against their dipole moment values for standard calibration curve. The range of the dipole moment values for calibration curve is pre-decided and the σ values for homogenous solutions of compositions below their saturation point can be measured with ± 1 × 10 − 5 s m − 1 .

Measurement of the shear storage modulus and viscosity of liquids using the Bleustein–Gulyaev wave

In the article, a method for measuring the rheological properties of viscoelastic liquids using the (surface shear) Bleustein–Gulyaev (B–G) wave is presented. By applying the perturbation method, one can prove that the change in the complex propagation constant of the B–G wave produced by the layer of viscoelastic liquid loading the waveguide surface is proportional to the shear acoustic impedance of the liquid. From the analysis performed by the authors, it results that the sensitivity of the B–G wave method used to determine the rheological parameters of the liquid is even higher than the sensitivity of the Love wave method. In this article, a practical measuring setup employing the B–G wave for the purpose of measuring the rheological properties of the liquid is presented. Subsequently, by measuring the change in the velocity and attenuation of the B–G wave, the shear impedance of the liquid was evaluated. Knowledge of the shear impedance of the investigated liquid then made it possible to calculate, for a given rheological model, the shear storage modulus μ and viscosity η of the investigated liquid. Measurements of liquid viscosity performed using the B–G wave method were compared to those obtained from the static capillary (Ubbelohde) method.

Precise measurement of liquid viscosity and surface tension with an improved oscillating drop method.

An improved oscillating drop method was developed to measure the surface tension and viscosity of a liquid without any external forces under microgravity conditions. The combination of a drop levitation system, a laser backlight system, and a line sensor enables the properties to be measured precisely. The surface tension value from 68.9+/-4.3 mN/m to 71.8+/-4.5 mN/m and the viscosity value of 0.92x10(-3) Pa s were obtained at 23.5 degrees C for pure water. These values agreed quite well with the reported value.

Rheological measurements using microcantilevers

The use of microcantilevers in rheological measurements of gases and liquids is demonstrated. Densities and viscosities of both gases and liquids, which can range over several orders of magnitude, are measured simultaneously using a single microcantilever. The microcantilever technique probes only minute volumes of fluid (<1 nL), and enables in situ and rapid rheological measurements. This is in direct contrast to established methods, such as “cone and plate” and Couette rheometry, which are restricted to measurements of liquid viscosity, require large sample volumes, and are incapable of in situ measurements. The proposed technique also overcomes the restrictions of previous measurements that use microcantilevers, which are limited to liquid viscosity only, and require independent measurement of the liquid density. The technique presented here only requires knowledge of the cantilever geometry, its resonant frequency in vacuum, and its linear mass density. A simple yet robust calibration procedure is des...

A Diode-Laser Based Automated Timing Interface for Rapid Measurement of Liquid Viscosity

We describe an exercise in experimental design suitable for the undergraduate laboratory, involving the construction of an automated timing interface for laminar liquid flow in glass. In many instructional physical chemistry laboratories, viscometry is introduced through measurements on polymer solutions using the principle of laminar flow. The design and construction of the interface are both part of the exercise. The digital timing scheme allows high relative precision even with very short (1s) flow times, making the use of smaller sample volumes feasible.

Liquid Viscosity Measurement Using Plate Mode Shear Horizontal Waves on a Piezoelectric Ceramic Thin Plate

Numerical analysis results of the propagation characteristics of multiple mode shear horizontal (SH) waves along a piezoelectric ceramic thin plate with liquid loading on one of two boundary surfaces are described. The fractional phase velocity changes for S0, A0 and S1 mode SH waves have linear dependences on the square root of liquid viscosity under the electrically shorted boundary condition of both surfaces of the substrate. The mechanical displacement in the liquid layer decays exponentially with the distance from the substrate-liquid interface. The existing depth of the displacement in the liquid layer increases with liquid viscosity in the form of a linear relationship to the square root of liquid viscosity. The measurement of liquid viscosity using two modes of SH waves is carried out. The measured results for water solutions of glycerol using S0 and A0 mode SH waves show linear dependences between the fractional velocity change and the square root of liquid viscosity, and are consistent with the theoretical values.

Liquid Viscosity Measurement Using SH Wave Propagation Characteristics on Piezoelectric Ceramic Thin Plate

Liquid viscosity measurement using shear horizontal (SH) wave propagation characteristics on a piezoelectric ceramic thin plate is described. The mode conversion loss associated with the compressional component U3 is zero, because the SH wave on the piezoelectric ceramic substrate poled along the horizontal axis has only the horizontal component U2, The IDT has a much larger electromechanical coupling factor for the S0 mode SH wave than that of the SH surface acoustic wave (SAW). The metal-coated condition of the liquid-loaded surface is essential for detecting the liquid viscosity. There exists a linear relationship between the fractional phase velocity change of the S0 mode and the square root of the liquid viscosity. The measured results on liquid viscosity using the S0 mode SH wave devices, for some concentrations of glycerol-water solutions, are in good agreement with the theoretical prediction.

Gravimetric capillary method for kinematic viscosity measurements

A novel version of the capillary method for viscosity measurements of liquids is presented. Viscosity data can be deduced in a straightforward way from mass transfer data obtained by differential weighing during the gravity-induced flow of the liquid between two cylindrical chambers. Tests of this technique with water, carbon tetrachloride, and ethanol suggest that this arrangement provides an accuracy of about ±1%. The technique facilitates operation under sealed, isothermal conditions and, thus can readily be applied to reactive and/or high vapor pressure liquids.

Analysis of errors of liquid viscosity measurement with a vibration viscosimeter

Analysis of errors of liquid viscosity measurement with a vibration viscosimeter

Simple torque magnetometer for anisotropy measurements in magnetic thin-film media

A simple and novel torque magnetometer for the magnetic anisotropy measurements of magnetic thin-film samples is described. A Brookfield LVTD viscometer, normally used in the viscosity measurements of liquids and fluids, is utilized as a torque measuring device. A HP series 310 computer along with the HP 7090 measurement plotting system interfaced to the torque magnetometer perform data acquisition, any calculations required for data correction, and plotting of the torque curves.

An automated falling-cylinder high pressure laser-Doppler viscometer

A microcomputer-controlled optical viscometer for the measurement of the viscosity of liquids under pressure is reported The viscometer is of the falling-cylinder type with a measurement range greater than six decades making it well suited for viscosity measurements of liquids with very large viscosity pressure coefficients. Results are presented for a range of alkanes and polypropylene glycol derivatives.

The use of the DME for continuous viscosity measurements of liquids

The use of the DME for continuous viscosity measurements of liquids

Viscosity Measurements of Liquids by the Oscillating Disc Method

WITH reference to the advantage of this method described by A. van Itterbeck1, it may be said2 that another advantage it has over the capillary stream method lies in the insensitivity of the disc experiments to the presence of dust particles as compared with the sensitivity of the capillary method.