Influence of Fillers on the Viscosity Properties of One-Pack Polyurethane Sealants

2021 ◽  
Vol 410 ◽  
pp. 605-610
Author(s):  
Kseniya A. Timakova ◽  
Yuriy T. Panov ◽  
Evgeniy A. Timakov
Keyword(s):  
Shear Rate ◽  
Dynamic Viscosity ◽  
Sharp Increase ◽  
Sharp Decrease ◽  
Shear Forces ◽  
Complex Orientation ◽  
Developed Surface ◽  
Mineral Fillers ◽  
Constant Shear Rate ◽  
Shape Of Particles

The paper investigates the effect of fillers on the viscosity properties of one-pack polyurethane sealants. It is noted that with the introduction of such mineral fillers as Mikarb, Midol, MTD2 chalk and aluminum hydroxide, the dynamic viscosity of the composition increases uniformly, while when filled with chemically precipitated Calofort SV chalk and MT-GShM talc, an abnormally sharp increase in viscosity is observed. Such an increase in viscosity for Calofort SV is explained by a highly developed surface, in contrast to other fillers. Talc is characterized by a plate-like shape of particles, which leads to a complex orientation of talc particles in the composition and shear difficulties.It was found that a sealant filled with chemically precipitated chalk has more than 100 pts. wt.(parts by weight), per 100 pts. wt. of the prepolymer under the influence of shear forces (at a constant shear rate) during the first 10 minutes of exposure, a sharp decrease in viscosity is observed, which is characteristic of thixotropic compositions, reaching a constant value after 5-10 minutes. After 10 minutes, the thixotropy of the sealant is restored. Talc does not impart thixotropic properties to the sealant composition.

scholarly journals Theoretical rheological models for olive oil

2020 ◽  
Vol 2 (3) ◽  
pp. 122-127
Author(s):  
Ioana Stanciu
Keyword(s):  
Shear Rate ◽  
Olive Oil ◽  
Dynamic Viscosity ◽  
Exponential Dependence ◽  
Rheological Models ◽  
Shear Rates ◽  
Constant Shear ◽  
Exponential Decline ◽  
Increasing Temperature ◽  
Constant Shear Rate

This paper proposes new rheological models for olive oil. The purpose of this study was to find an exponential  dependence between temperature and dynamic viscosity of olive oil, using one equation. Equation constants lnη0, A1 and t1 were determined by fitting exponential. The olive oil have investigated using a Haake VT 550 Viscotester developing shear rates ranging between 3 and 120 s-1 and measuring viscosities from 104 to 106 mPa·s when the HV1 viscosity sensor is used. Olive oil dynamic viscosity decreases with increasing temperature at constant shear rate.  Plotting the ln dynamic viscosity depending on temperature shows an exponential decline.

scholarly journals Computer aided optimisation of a constant shear-rate micro-channel contraction

2009 ◽  
Vol 50 ◽  
pp. 1004
Author(s):  
Simon Higgins ◽  
Gregory J Sheard ◽  
Andreas Fouras ◽  
Kerry Hourigan
Keyword(s):  
Shear Rate ◽  
Micro Channel ◽  
Constant Shear ◽  
Computer Aided ◽  
Constant Shear Rate

scholarly journals Zonal features of the dynamics of humus content in soils of Chernihiv region

2021 ◽  
pp. 115-125
Author(s):  
O. Grischenko ◽  
S. Romanova ◽  
V. Zapasnyi ◽  
I. Shabanova
Keyword(s):  
Organic Matter ◽  
Green Manure ◽  
Sharp Increase ◽  
Humus Content ◽  
Weighted Average ◽  
Sharp Decrease ◽  
Organic Fertilizers ◽  
Climatic Zones ◽  
Sown Area ◽  
Green Manure Crops

The humus condition of soils of Chernihiv region has been studied. The dynamics of humus content in the soils of the region during six rounds (1986–2015) of agrochemical certification of agricultural lands is generalized and analyzed. In comparison with the 5th round (1986–1990), there was a discrepancy between the processes of stabilization and increase of humus content in most districts and in the region as a whole in the ninth round (2006–2010), and in some districts in the tenth round (2011–2015) against the background of a sharp decrease in the application of organic fertilizers. It was found that the stabilization of humus content in the soils of the region during the V–VIII rounds of agrochemical certification and a sharp increase in its content in the ninth round, against a significant reduction of organic matter, correlates with the withdrawal of eroded, low-yielding lands with low humus content (r=0.76). Analyzing the dynamics of humus content over thirty years of research,it was found that its content has increased in all climatic zones, as well as in nineteen of the twenty-two districts of the region. The increase of the indicator is in the range of 0.01–0.72%, while in all districts there is a significant reduction of the surveyed areas and only in three districts of the region there is a decrease in the humus content. According to the results of the 10th round of agrochemical certification, the soils of Chernihiv region are characterized by an average humus content of 2.41%. The highest humus content is characterized by the soils of Bakhmatsky (3.56%), Talalaivsky (3.33%) and Pryluky (3.32%) districts, and the lowest — NovgorodSiversky (1.57%). Increasing the sown area of green manure crops, plowing straw and the use of other elements of biologization of agriculture are important factors in increasing the weighted average humus content in the soils of Chernihiv region.

GRAFT COPOLYMERS OF STYRENE AND METHYL METHACRYLATE: PART II: VISCOSITY BEHAVIOR

1956 ◽  
Vol 34 (8) ◽  
pp. 1027-1036 ◽  
Author(s):  
M. H. Jones
Keyword(s):  
Shear Rate ◽  
Methyl Methacrylate ◽  
Graft Copolymers ◽  
Free Fall ◽  
Capillary Viscometer ◽  
Linear Polymers ◽  
Viscosity Behavior ◽  
Shear Gradient ◽  
Constant Shear Rate ◽  
Made In

A study of the viscosity behavior of the graft copolymers described in Part I has been made with dilute solutions in benzene at 25 °C. Although the slope constants of the Huggins equation increase with the frequency of branching when measurements are made in a capillary viscometer under 'free fall' conditions, this is shown to be attributable to the dependence of viscosity on shear gradient. At a constant shear rate, the Huggins k′ values approximate to those of linear polymers. It is suggested that the marked increase in viscosity observed with decreasing shear rate for the graft copolymers is due to molecular entanglement.

Acoustic Heating Produced in the Thermoviscous Flow of a Shear-Thinning Fluid

2011 ◽  
Vol 36 (3) ◽  
pp. 629-642
Author(s):  
Anna Perelomova
Keyword(s):  
Shear Rate ◽  
Differential Form ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Nonlinear Flow ◽  
Dynamic Equations ◽  
Weakly Nonlinear ◽  
Piecewise Constant ◽  
Shear Thinning Fluid ◽  
Constant Shear Rate

AbstractThis study is devoted to the instantaneous acoustic heating of a shear-thinning fluid. Apparent viscosity of a shear-thinning fluid depends on the shear rate. That feature distinguishes it from a viscous Newtonian fluid. The special linear combination of conservation equations in the differential form makes it possible to derive dynamic equations governing both the sound and non-wave entropy mode induced in the field of sound. These equations are valid in a weakly nonlinear flow of a shear-thinning fluid over an unbounded volume. They both are instantaneous, and do not require a periodic sound. An example of a sound waveform with a piecewise constant shear rate is considered as a source of acoustic heating.

DIFFERENCES IN STEADY CHARACTERISTICS AND RESPONSE TIME OF ERF ON ROTATIONAL FLOW BETWEEN ROTATING DISK AND CONCENTRIC CYLINDER

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1050-1056 ◽  
Author(s):  
K. SHIMADA ◽  
H. NISHIDA ◽  
T. FUJITA
Keyword(s):  
Shear Rate ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Current Density ◽  
Rotating Disk ◽  
Settling Time ◽  
Rotational Flow ◽  
Concentric Cylinder ◽  
Constant Shear Rate

We made an experimental investigation of the steady characteristics of torque, current density, and response time of ERF on rotational flow of the disk and the concentric cylinder. We used smectite particles suspension ERF and D.C. electric field. We compared the steady shearstress, current density, and the rise and settling time of the concentric cylinder and with those of the rotating disk. Then we clarified the differences. At a larger electric field strength, the shear stress, yield stress, and apparent viscosity to a constant shear rate in the case of the rotating disk are larger than they are in the case of the rotating concentric cylinder. However, at a larger electric field strength, the current density to a constant shear rate in the case of the rotating disk is smaller than it is in the case of the rotating concentric cylinder. Rise time of torque in the case of the rotating disk is faster than it is in the case of the rotating concentric cylinder. However, rise time of current density in the case of the rotating disk is slower than it is in the case of the rotating concentric cylinder at a small electric field strength. On the other hand, the difference of settling time of torque and current density between the rotating disk and the rotating concentric cylinder is changed by the electric field strength and shear rate. The settling time of torque in the case of the rotating disk is faster than it is in the case of the rotating concentric cylinder at a large electric field strength and large shear rate. The settling time of current density in the case of the rotating disk is slower than it is in the case of rotating concentric cylinder at a small electric field strength. Based on these results, the rotating disk has an efficiency of obtained torque to given electric power greater than that of the rotating concentric cylinder.

Viscosity in Exploitation Time Analysis of the Lubricating Oil Used in the Combustion Engine of the Personal Car

2015 ◽  
Vol 220-221 ◽  
pp. 271-276 ◽  
Author(s):  
Grzegorz Sikora ◽  
Andrzej Miszczak
Keyword(s):  
Shear Rate ◽  
Dynamic Viscosity ◽  
Combustion Engine ◽  
High Shear Rate ◽  
Engine Oil ◽  
Lubricating Oil ◽  
High Shear ◽  
Oil Viscosity ◽  
Peltier Element ◽  
Engine Model

The aim of this study is to develop a mathematical model of the lubricating oil viscosity changes during the exploitation time of the engine.The aim was achieved by measurements of dynamic viscosity of engine oil used in a passenger car Volkswagen Touran equipped with a turbocharged diesel engine with a capacity of 2.0 liters. The recommended interval for oil change in this engine model is 30000 km. Oil used in this study was Shell Helix AV-L (viscosity grade SAE 5W30, designation VW: 50700).Viscosity tests were made on a Haake MARS III using two measuring systems. The first consisted of a plate-cone system with Peltier element for temperature stabilization. The second one is the high shear rate chamber with temperature control thermostat co-operating with ultra-A40 AC200 which can operate at temperatures ranging from-40 °C to +200 °C. The high shear rate chamber, consisting of a measuring cylinder and the rotor, the shear rate can achieve up to 200000 s–1.Dynamic viscosity measurements were performed at temperatures ranging from 20 °C to 90 °C.The results of the research are shown in the graphs and in tabular form. Obtained graphs made it possible to determine characteristics of the oil ageing for each mileages, temperatures and shear rates.

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