scholarly journals Viscosity and biodiesel characteristics of wild Canarium schweinfurthii Engl. fruit oil  

2018 ◽  
Vol 64 (No. 4) ◽  
pp. 169-175
Author(s):  
Ehiem James Chinaka
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Medical Model ◽  
Temperature Stability ◽  
Oil Viscosity ◽  
Shear Rates ◽  
Flow Behaviour Index ◽  
Different Temperatures ◽  
Fruit Oil ◽  
Behaviour Index

The viscosity of two varieties of Canarium schweinfurthiiEngl. fruits oil (large and long) were studied at four different temperatures (30, 40, 50 and 60<sup>o</sup>C) and three shear rates (7.91, 15.82 and 39.54 s<sup>–1</sup>). SurgiFriend Medical (model NDJ-5S) viscometer was used to carry out the study. Biodiesel characteristics of the oil were also investigated. The results showed that variety had no effect (P &lt; 0.05) on the viscosity of Canarium schweinfurthii Engl. fruit while temperature had especially at 50<sup>o</sup>C and above. The shear rate of 15.82 s<sup>–1 </sup>(12 rps) gave the lowest oil viscosity for both varieties. The oil from large fruit had the best temperature stability, low percentage viscosity (6.33%) variation and least activation energy (796.51 J·mol<sup>–1</sup>·K<sup>–1</sup>) while long variety had best biodiesel characteristic for safe handling. Temperature had no significant (P &lt; 0.05) effect on the consistency coefficient (C) and flow behaviour index (n) of both varieties of Canarium schweinfurthii Engl. fruits oil. Besides, oil from both fruit varieties is Newtonian fluids.

The Influence of Sewage Fat Composition on Rheological Behavior of Metal Injection Moulding

2014 ◽  
Vol 660 ◽  
pp. 38-42 ◽  
Author(s):  
Azriszul Mohd Amin ◽  
Mohd Halim Irwan Ibrahim ◽  
Rosli Asmawi ◽  
Najwa Mustapha
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Injection Moulding ◽  
Rheological Characteristic ◽  
Flow Behaviour ◽  
Characteristic Analysis ◽  
Metal Injection Moulding ◽  
Flow Behaviour Index ◽  
Binder Ratio ◽  
Behaviour Index

Influence of sewage ratio or Fat Oil Grease (FOG) on the feedstock rheological characteristic for optimal binder formulation in metal injection moulding is evaluated besides Polypropylene (PP) as a backbone binder. Powder loading of 62% of water atomised SS316L being used here to determine the possibility of the best binder formulation which could be optimised for optimal powder loading base on rheological characteristic analysis. Two binder formulations of PP to SF being selected here are 60/40, 50/50 and 40/60 accordingly with the powder loading of 62% each binder formulation. The analysis will be base on viscosity, shear rate, temperature, activation energy, flow behaviour index and moldability index. It is found that from rheological result views, binder with composition of 60/40 and 50/50 exhibit pseudoplastic behaviour or shear thinning where the viscosity decrease with increasing shear rate. For 40/60 binder ratio is not suitable since the behaviour of the flow indicates dilatants behaviour. After considering all the criteria in terms of flow behaviour index, activation energy, viscosity and mouldability index, binder with ratio of 60/40 is evolve as a good selections.

scholarly journals Use of helical ribbon mixer for measurement of rheological properties of fruit pulps

2013 ◽  
Vol 19 (No. 4) ◽  
pp. 148-153 ◽  
Author(s):  
P. Novotná ◽  
A. Landfeld ◽  
K. Kýhos ◽  
M. Houška ◽  
J. Strohalm
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Flow Behaviour ◽  
Rotational Rheometer ◽  
Shear Rates ◽  
Coaxial Cylinders ◽  
Helical Ribbon ◽  
Flow Behaviour Index ◽  
Average Shear ◽  
Behaviour Index

Fruit pulps contain fine particles of the flesh of the original fruit that are suspended in the fruit juice. This suspension has a tendency to settling or separation during measurements of its rheological properties in the rotational rheometer with coaxial cylinders (especially if the greater gap is used). In this case the use of a mixer is convenient. The mixer can serve as a tool for measurement of rheological properties and at the same time it can prevent the settling and it is not sensitive to the occurrence of greater particles in the measured fluid. The helical ribbon mixer was used in this work for measurement of five samples of fruit pulp. The mixer was calibrated by the use of Newtonian fluid of known viscosity (honey). The radius of the inner cylinder of hypothetical rotational rheometer was predicted from the assumption that mixer and cylinder exhibit the same torque necessary for the rotation at the same rotational speed. The average shear rate in the mixed pulp was predicted by using the relation valid for power law fluids and rheometer with coaxial cylinders. The radius (where the average shear rate was calculated) was chosen by the requirement that the shear rate would be almost independent of changes in the flow behaviour index valid for measured pulps. Firstly the flow behaviour index was predicted as a slope of torque vs. rotational speed dependence in log-log co-ordinates. It was found that the flow behaviour index varies in the range 0.2&ndash;0.3. The radius was predicted from a graph where shear rates for 0.2 and 0.3 are the same. Then the average shear rates were calculated from rotational speeds for individual flow behaviour indexes. Rheological properties measured by using a mixer correspond to those measured with a rotational rheometer with coaxial cylinders satisfactorily only in the case that the creeping flow regime was kept in the mixed fluid. The fruit pulps are strongly non-Newtonian fluids with very low values of the flow behaviour index around 0.2.

Characterization of the Rheological Behavior of Drilling Fluids

2020 ◽  
Author(s):  
Eric Cayeux ◽  
Amare Leulseged
Keyword(s):  
Shear Rate ◽  
Rheological Behavior ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Shear Rates ◽  
Operation Conditions ◽  
Fluid Systems ◽  
Different Temperatures ◽  
The One ◽  
Shear Stress Response

Abstract It is nowadays well accepted that the steady state rheological behavior of drilling fluids must be modelled by at least three parameters. One of the most often used models is the yield power law, also referred as the Herschel-Bulkley model. Other models have been proposed like the one from Robertson-Stiff, while other industries have used other three-parameter models such as the one from Heinz-Casson. Some studies have been made to compare the degree of agreement between different rheological models and rheometer measurements but in most cases, already published works have only used mechanical rheometers that have a limited number of speeds and precision. For this paper, we have taken measurements with a scientific rheometer in well-controlled conditions of temperature and evaporation, and for relevant shear rates that are representative to normally encountered drilling operation conditions. Care has been made to minimize the effect of thixotropy on measurements, as the shear stress response of drilling fluids depends on its shear history. Measurements have been made at different temperatures, for various drilling fluid systems (both water and oil-based), and with variable levels of solid contents. Also, the shear rate reported by the rheometer itself, is corrected to account for the fact that the rheometer estimates the wall shear rate on the assumption that the tested fluid is Newtonian. A measure of proximity between the measurements and a rheological model is defined, thereby allowing the ranking of different rheological behavior model candidates. Based on the 469 rheograms of various drilling fluids that have been analyzed, it appears that the Heinz-Casson model describes most accurately the rheological behavior of the fluid samples, followed by the model of Carreau, Herschel-Bulkley and Robertson-Stiff, in decreasing order of fidelity.

The Influence of Temperature and Shear Rate on the Viscosity of Selected Motor Oils

2013 ◽  
Vol 199 ◽  
pp. 188-193 ◽  
Author(s):  
Adam Czaban
Keyword(s):  
Diesel Engine ◽  
Shear Rate ◽  
Sliding Friction ◽  
Full Range ◽  
Lubricating Oil ◽  
Initial Structure ◽  
Oil Viscosity ◽  
Lubricating Oils ◽  
Shear Rates ◽  
Motor Oils

One of the most important physical quantities which has an influence on bearings and micro-bearings functioning is the viscosity of a lubricant. The data about a viscosity value dependence on temperature and shear rate are essential for designing sliding friction pairs. In design calculations usually there is assumed that a lubricant is a Newtonian fluid, therefore viscosity is constant over the full range of shear rates. During operation of friction pairs the contamination particles get into a lubricant and this causes that the lubricant becomes a non-Newtonian pseudoplastic or viscoelastic fluid. A similar effect on lubricating oil properties have combustion products or special performance additives. Furthermore, a lubricating oil ages and wears out, i.e. during its operating the initial structure of a particles is destroyed which can cause the change of the oil viscosity and lubricity values. The aim of this work is to determine the dynamic viscosity values in dependence on temperature and shear rate for selected new and used lubricating oils. In this research motor oils for passenger vehicles and tractors were investigated. This paper presents the results of measurements of the viscosity changes, in dependence on shear rate and temperature, made for the new and used oils. One of the investigated oils is Superol CC-40, which was used in four-stroke 4562 cm3 diesel engine for twenty months, which corresponds to 250 hours of operating. The second of investigated oils is Shell Helix Ultra AV-L which was used in four-stroke 2000 cm3 diesel engine for ten months at a distance of 15 000 kilometers. The viscosity measurements for the new and used lubricating oils were made with the Thermo Scientific Haake Mars III rheometer, in the range of temperatures from 10°C to 120°C and of shear rates to 51000 1/s. Moreover, the analysis of wear products, contaminants and additives in the investigated new and used lubricating oils was made with the rotating disc electrode atomic emission spectrometer Spectro Incorporated Spectroil Q100, which gives possibility to determine 22 most common elements which occur in motor, turbine and gear oils. The obtained information will be used in future studies related to hydrodynamic lubrication of slide bearings and micro-bearings. It also may be useful for designing bearings and sliding friction pairs.

PREDICTING THE FLOW PROPERTIES OF POLYAMIDE NANOCOMPOSITES BY USING VINOGRADOV-MALKIN MODEL

2015 ◽  
Vol 9 (3) ◽  
pp. 2446-2452
Author(s):  
Tomasz Mariusz Majka ◽  
Marcin Majka ◽  
Muhammad Kamrul Hasan
Keyword(s):  
Shear Rate ◽  
Flow Direction ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Polyamide 6 ◽  
Flow Index ◽  
Melt Flow ◽  
Melt Flow Rate ◽  
Shear Rates ◽  
Different Temperatures

This article reports the prediction of the theoretical flow curves of polyamide composites by using Vinogradov-Malkin model. Determination of the melt flow index of polymeric materials is the first step to study viscosity-shear rate relationship. The viscosity of the composites at different temperatures were calculated by using the Williams, Landel'a and Ferry (WLF) equation. Other important rheological characteristics were calculated by using appropriate equations. One point method is employed to correlate the changes in viscosity with temperatures. As expected, it is found that incorporation of nanoclay to polyamide 6 (PA6) significantly decreases the Melt Flow Rate of the composites and hence, increases density. Addition of stabilizer further increases density of the PA6/nanoclay composites. The simulations of viscosity curves for PA6 composites were carried out at measurement temperature, 240°C and in the range of 180°C - 350°C with shear rate of 10-1 – 103 1/s. It is found that addition of nanoclay and stabilizer to PA6 decreases viscosity of the composites in the order of PA6/OMMT > PA6 > PA6/I1098 > PA6/OMMT/I1098 > PA6/MMT/I1098 > PA6/MMT. At higher shear rates, viscosity decreases in the same sequence as low shear rates. At further higher shear rates (> 1000 1/s), filler particles are arranged in the flow direction thus exerting no significant effect on viscosity of composites both with and without the stabilizer. During injection moulding in the shear rate ranging from 101 – 104 1/s at 240°C temperature, it is evident that viscosity decreases drastically with increase in shear rate.

scholarly journals Rheological and Prediction of melt viscosity flow curves for blend of Polycarbonate (PC) and Polyacrylonitrile butadiene styrene (ABS)

2019 ◽  
Vol 12 (6) ◽  
pp. 33-40
Author(s):  
Alsaeed Douaa ◽  
Deri Fawaz
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Temperature Dependence ◽  
Melt Viscosity ◽  
Flow Curves ◽  
Actual Measurement ◽  
Shear Rates ◽  
Different Temperatures ◽  
Experimental Validity ◽  
Butadiene Styrene

A knowledge of the variation of melt viscosity of thermoplastic polymers with both shear rate and temperature is of considerable importance to plastics engineers as well as to polymer rheologists. The Actual measurement of melt viscosity at large number of temperatures and shear rates is frequently a tedious and time-consuming task. The experimental validity for superimposing Log shear stress – Log shear rate curves at different temperatures along the log shear rate axis has been established for the mixture of (polycarbonate and polyacrylonitrile butadiene styrene). The temperature dependence of the resultant shift factors has been determined to predict viscosities as a function of temperature and shear rate is discussed

scholarly journals Fractal theory of non-Newtonian oil viscosity based on the mutual interaction of colloidal particles: a review and new results

2021 ◽  
pp. 26-46
Author(s):  
V.I. Lesin
Keyword(s):  
Shear Rate ◽  
Physical Model ◽  
Colloidal Particles ◽  
Fractal Structure ◽  
Fractal Theory ◽  
Experimental Studies ◽  
Oil Viscosity ◽  
Shear Rates ◽  
Model Sample ◽  
Individual Particles

To describe the viscosity of oil, the author proposed a theory based on a new physical model, which takes into account the interaction of individual colloidal particles and their aggregates of fractal structure. This process is accompanied by the addition of individual particles to aggregates and by their separation under the action of shear stress, which is reflected in the energy consumption of the fluid movement and manifests itself as a dependence of the viscosity on the shear rate. The purpose of the review is to demonstrate the application of fractal viscosity theory to interpret the results of known experimental studies. The review also contains the results of new experimental studies of a model sample of oil to illustrate a number of statements of the theory. The detailed parameters of the physical model are specified, on the basis of which a fractal theory of viscosity is proposed; a system of two equations is obtained that allows to describe the dependence of viscosity on the shear rate and time. It is demonstrated that the conclusions drawn from the theory correspond to the known and newly obtained experimental data. The regularities of viscosity relaxation predicted experimentally by the theory with increasing and decreasing shear rates are confirmed. A methodology based on the laws of thermodynamics is proposed that allows to select the mode of shear rate action on heavy oil to reduce its viscosity.

scholarly journals Improvement Viscosity Index of Lubricating Engine Oil Using Low Molecular Weight Compounds

2019 ◽  
Vol 7 (1) ◽  
pp. 14-17 ◽  
Author(s):  
Shenwar A. Idrees ◽  
Lawand L. Mustafa ◽  
Sabah S. Saleem
Keyword(s):  
Polar Solvent ◽  
Viscosity Index ◽  
Temperature Stability ◽  
Polar Molecule ◽  
Engine Oil ◽  
Lubricating Oil ◽  
Oil Viscosity ◽  
Different Temperatures ◽  
London Dispersion ◽  
Molecular Forces

the effect of polarity of solvent on the viscosity and viscosity index of lubricating engine oil has been studied using ethanol as an example of polar solvent and toluene as an example of non-polar solvent at different solvent ratios and ambient temperature and additionally other experiments have been done at five different temperatures including 100 oC. So that, the activation energy of viscous flow (Ea) was calculated, and for this purpose Arrhenius viscosity-temperature dependence has been applied and the results were 42.128, 29.256 and 35.417KJ/mole for lubricating engine oil mixed with ethanol, toluene and no additives in turn. It additionally shows that adding polar solvent to lubrication engine oil viscosity increases this may be due to the fact of strong inter molecular forces that found in polar molecules such as hydrogen bonding in ethanol makes the solution forces stronger as a result higher viscosity. However, adding non-polar solvent decreases viscosity because of small size of toluene and both paraffinic lubricating oil and toluene have same London dispersion inter molecular forces. Last not least, the result shows that engine oil mixed with non-polar molecule gives more temperature stability than that of polar molecule giving viscosity index (VI) 366 and 580 respectively.

scholarly journals Absolute Viscosities of Vegetable Oils at Different Temperatures and Shear Rate Range of 64.5 to 4835 s−1

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Lemuel M. Diamante ◽  
Tianying Lan
Keyword(s):  
Shear Rate ◽  
Vegetable Oils ◽  
Rice Bran Oil ◽  
Activation Energies ◽  
Coaxial Cylinder ◽  
Walnut Oil ◽  
Viscosity Change ◽  
Shear Rates ◽  
Different Temperatures ◽  
The Absolute

A study was carried out to determine the effect of higher shear rates (64.5 to 4835 s−1) on the absolute viscosities of different vegetable oils at different temperatures (26 to 90°C). The absolute viscosities of the different vegetable oils were determined using a Lamy Viscometer RM100, a rotating viscometer with coaxial cylinder. The torque of each sample at different temperatures was recorded at different shear rates. Based on the rheograms (plot of mean shear stress against shear rate), all of the vegetable oils studied were found to be Newtonian fluids. Rice bran oil was the most viscous (0.0398 Pa·s at 38°C) while walnut oil was the least viscous (0.0296 Pa·s at 38°C) among the oils studied. The higher shear range used did not significantly affect the absolute viscosities of the vegetable oils at the different temperatures. The absolute viscosities of the vegetable oils decreased with increasing temperature and can be fitted with an Arrhenius type relationship. The activation energies for the different vegetable oils ranged from 21 to 30 kJ/mole. The peanut and safflower oils had the highest and lowest activation energies, respectively. This means that greater energy was needed to effect a viscosity change in the peanut oil.

Rheological Behavior of Hybrid Rubber Nanocomposites

2005 ◽  
Vol 78 (5) ◽  
pp. 806-826 ◽  
Author(s):  
Abhijit Bandyopadhyay ◽  
Mousumi De Sarkar ◽  
Anil K. Bhowmick
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Die Swell ◽  
Experimental Conditions ◽  
Shear Rates ◽  
Silica Nanocomposites ◽  
Marginal Increment

Abstract Melt rheological behavior of acrylic rubber (ACM)/ silica and epoxidized natural rubber (ENR)/ silica hybrid nanocomposites prepared by using sol-gel technique at room temperature was studied for the first time in a Monsanto Processability Tester (capillary rheometer) at nine different shear rates and three different temperatures (100 °C, 110 °C and 120 °C). Tetraethoxysilane (TEOS) was used as the precursor for silica, and water to TEOS mole ratio was maintained at 2:1 throughout the experiments. The loading of TEOS was 10, 30 and 50 wt% with respect to the rubber and the pH of the medium was maintained in the range of 1.0–2.0 by the addition of appropriate amount of concentrated HCl. The shear viscosity showed marginal increment even at higher nanosilica loading for the rubber/ silica nanocomposites. All the compositions displayed pseudoplastic behavior and obeyed Power Law model within the experimental conditions. The reinforcement factor (RF) calculated from the ratio of the viscosities of the filled and the unfilled systems was found to increase with nanosilica content at a particular shear rate. ENR/ silica nanocomposites displayed higher increment of RF compared to ACM/ silica system, which may be due to better polymer-filler interaction in the former. The RF remained almost constant for both the systems with the variation of temperature. The die swell of the nanocomposites was always lower than that of the gum rubber sample, though the nature of variation of die swell with shear rates was different for ACM and ENR nanocomposites. In both the cases, the die swell was found to decease with increase in temperature. The variation in activation energy with the experimental shear rates was also calculated, where the hybrids displayed a decreasing trend in activation energy with the increase in shear rate.

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