Viscosity - Science topic

Is viscosity dependent on heating rates? Please explain in detail. Also, provide a research article or method that explains how to calculate viscosity using Differential Scanning Calorimetry (DSC) data.

Hello!

When we purchase a biodegradable polyester (PLA, PCL, PHB and others), the manufacturer usually reports the viscosity of a chloroform solution of this polymer. For example, "viscosity ~1.5 dL/g for 0.1% solution at 25C".

I want to use the Mark-Kuhn-Houwink equation to calculate the molecular weight based on this data, and I face several problems.

1. The viscosity provided by the manufacturer seems to be the inherent viscosity rather than the intrinsic viscosity. Is there a reasonable way to estimate the intrinsic viscosity based on a single concentraion point?

2. The solutions of polyesters in chloroform, HFIP and the other commonly used solvents are widely used and extensively studied. I am almost sure that the relations between the molecular weights, concentrations and viscosities are long known and perfectly described. Is there a simple and straightforward source where I can find this information?

I know storing PVA aqueous solutions at room temperature causes aging which means cross-linkig and hydrogen bonds formation, But I need to accelerate its aging process to gain suitable viscosity for electrospinning without adding aging agents such as acids.

(a) complex rheology of polymer fluids;

(b) complex topology of the pore-network geometry?

Hello, My name is Nathan Ruas Alves, I am a civil engineer graduated from the Federal University of Uberlândia and I am currently studying for a master's degree in Civil Engineering with an emphasis on Structures. I would like to ask for your kind collaboration in solving a problem I am facing in my research. I have tried several approaches, but so far, I have not been successful. I am studying smooth concrete slabs reinforced with non-metallic GFRP rebars. The slabs are being simulated by a quarter of the entire slab to facilitate processing. I am using a mesh size of 35 mm, viscosity of 0.0001 and dilatancy angle of 43º. The interaction of the concrete slab with the GFRP rebars is of Embedded region and the Actuator (element considered as rigid in numerical modeling) with the top of the slab where the load is applied was of Constraint type Tie type. For the constitutive model of the concrete I am using the fib Model Code 2010 model for compression and for tension I am using Hordijk (1991). It is worth mentioning that I am using symmetry boundary conditions on the faces of the slabs! The concrete compression and tension damage model that I am using is from the formulation proposed by Yu et al. (2010) which represents a simplified method, as it consists only of subtracting from the unit the ratio between the acting stress and the maximum resistant stress. What I don't understand is why in all the simulations I perform mixing dilatancy or viscosity angles or meshes the stress x displacement curve always looks like this before the peak. How can I reduce this peak to get closer to the experimental one?

I have made a NaDES using choline chloride and leaf extract. It is liquid at 150-degree temperature but it becomes solid at room temperature. To use it as a solvent, I need it to remain liquid at room temperature too. can you suggest how to make it liquid or reduce viscosity.

With a solid loading of 51%, the viscosity of my Si₃N₄ slurry is around 8000 to 12000 mPa.s. Removing pinholes at this high viscosity is proving to be quite challenging, and these pinholes are causing defects in the green sheet. Could anyone share insights or suggestions on how to address this issue and achieve a defect-free substrate?

Can anyone tell what is the dynamic viscosity value of PCM OM-42 in liquid phase required for numerical modeling. In literature I am not getting exact value. (OM-42 PCM, by Pluss )

Hello, eveyone!

Does anyone here work with β-glucanase and have a recommended methodology for quantifying its activity? I’ve come across assays based on viscosity, reducing sugar production, and commercial kits. However, I’m wondering which method would be the most suitable. Thank you!

1. Despite the efficacy of Surfactant Flooding (which essentially improves the pore-scale displacement efficiency by reducing oil-water IFT any by modifying rock wettability), to what extent, the economic feasibility of ‘Free Surfactant Injection’ during a typical Chemical EOR – could positively be addressed - through the utilization of ‘Surfactant Carriers’, towards mitigating extensive losses through adsorption or precipitation on the rock surfaces?

2. Feasible to deduce ‘A Time Dependent Chemical Structure’ of Polymerswhich could possibly act as both ‘Wettability Modifiers’ as well as ‘Surfactant Carriers’, in addition to its conventional expectation on enhancing the volumetric sweep efficiency by reducing the oil-brine mobility ratio through amplified viscosity?

3. Since, HPAM’s (which is the prevalent synthetic polymer in EOR flooding) viscosifying potential gets diminished under the presence of high-saline brine, and also, due to HPAM’s susceptibility to thermal and mechanical degradation impacts the longevity of the polymer flooding, can the application either Biopolymers or HPAM Derivatives (amphoteric hyper-branched polymer derivatives) (cellulose, chitosan & galactomannan-guar) could really enhance EOR system stability?

I am doing an experiment wherein we are depositing some hydrophilic nano-particles on a functionalised surface. We are then displacing the aqueous phase with a high viscosity oil phase. However, we are losing approx. 10-20% of the aqueous phase as a hydration layer.

To resolve this we have increased viscosity of oil, added Tween 20 to oil, mixed 10% IPA in aqueous phase. We were able to reduce the liquid loss but it was not repeatable. In addition, use of IPA and ethanol is detrimental to binding of particles to the surface.

As per constraints of our system, we are unable to change flow rate and coating of the channel.

I would appreciate any suggestions on this?

A yellow emulsion appears during the synthesis of poly(amic acid), along with a lack of viscosity, Why?

Some sources say it is treated as Newtonian as ethylene glycol has a higher viscosity than water, which affects the flow characteristics in simulations. But some also say it is non-Newtonian.

Currently, I am conducting dynamic light scattering measurements in different THF/water mixtures (in volume fractions) at 23 ºC and I was wondering whether there are any published data for the related viscosity and refractive index parameters.

There are Magnesium-based vanadium inhibitors on the market with low viscosities. How are they produced? specifically 28% Mg-containing ones (which are referred as polymerized Mgs) with such high velocity and low viscosity? How can I know about the ingredients and production route of the process?

We know that the LBE is non-dimensional. If I want to introduce the Carreau model in LBM, what are the ways to make the prescribed dimensional model into non-dimensional form, especially when the zero and infinite shear-rate viscosities are expressed in Pa s. Some references to this will be of great help. Also how to take care of the Carreau number.

Attached figure is from https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/numerical-simulation-of-flow-of-a-shearthinning-carreau-fluid-over-a-transversely-oscillating-cylinder/70BA8A4937C5A0531EF5B1175CEE4E7D

I need the density and viscosity of a molecular fluid under relatively high pressures, I expect something around 500 MPa. This kind of measurement is way outside my field, and I can find only very few groups who appear to be capable of it, all of which refused for technical reasons so far. Does anyone know a collaborator for high pressure rheology and/or densitometry?

Hello everyone, Does anyone have any idea on how to deal with such warning messages in Abaqus where the CDP model is being used? My model consists of concrete(C3D8R element) and steel bar reinforcements(T3D) as embedded elements. I have already tried to increase the value of the viscosity parameter for concrete but it didn't work for me. It has caused cutback trouble to my simulation because the warning messages exceed the limit. I have attached an image file from my simulation. Please kindly find it. Any help would be highly appreciated. Thanks!

The question is not about the mixing rule of hetergeneous slags (one liquid + one solid).

It's about the mixing rule of viscosity when two oxide liquids mix.

When the slag compositions hit a region where there is a miscibility gap of two oxide liquids, they should physically mix (or form emulsion that one is suspended in another) as they don't dissolve into each other.

The experiment normally reports a viscosity value, but behind the measurement, what is really this viscosity value for such case - is it the viscosity after mixing or happens to be one of the oxide liquid?

It seems we can easily predict the viscosity of two mixing liquid oxides using the equations in the attached snapshot.

Can I have your opinion on the viscosity mixing rule of two oxide slags or liquids ? How do we model or predict it ?

Thank you in advance.

I am currently working on a formulation. I'm however getting a higher viscosity reading (in centipoise) than what my counterpart in another laboratory is getting at same spindle and same speed. I have tried to do some root cause analysis and I realized our viscometers are of entirely different models.

While I use Brook field DV2T in my Lab, my counterpart uses Brook field RVT. So I will like to ask

I'm currently working with lignin solutions in sodium hydroxyde and I've collected data on the solutions' viscosity at different NaOH and lignin concentration. The viscosity seems to be correlated mainly with lignin concentration by a power model (the viscosity is proportional to the fourth power of the concentration), yet it still shows some deviations for simillar lignin concentrations at different NaOH concentrations. I've tried working with relative, specific, and reduced viscosity, with the pH, and with lots of different variations of this power model that I inicially proposed, but none of them solved these minor discrepancies. Having in sight that lignin is considered to behave as a branched polyelectrolyte in NaOH solutions, is there a general model that can be tried? One that counts the ionic strength or something simillar? I found quite hard to find any simple model that could be used, yet I think it's quite hard that none has been proposed this far.

Hello all,

Some sources say it is treated as Newtonian as ethylene glycol has a higher viscosity than water, which affects the flow characteristics in simulations. But some also say it is non-Newtonian.

well I have waterborne films and I want to check their viscosity, I am guessing it is possible through tensile strength test, can anyone help me

Reservoir Engineering

Deviations from Original Darcy’s Law

1. What was the need for Muskat to replace original hydraulic gradient by pressure gradient?

2. What was the need for Wyckoff to separate Darcy’s original constant of proportionality into permeability (rock property) and viscosity (fluid property)?

3. How about permeability depending on gas pressure, i.e., depending on fluid property (Knudsen-effect/Slippage-effect/Klinkenberg-effect) as well?

4. How about the significance of deviation of Darcy’s law @ very low fluid velocities – associated with consolidated, confined oil and gas reservoirs?

Whether fluid would require a definite threshold gradient in order to shear and to begin flowing?

Would it also influence reserve forecast?

5. How about the application of Darcy’s law for non-Newtonian fluids (where, viscosity remains a function of applied shear rate)?

6. How about non-Darcy flow or post-Darcy flow associated with the non-linear variation of flow velocity with respect to the applied pressure gradient (which has a significant influence on well performance)?

7. In radial flow, the cross sectional area to flow increases, which causes a decrease in fluid velocity for any, given constant flow rate. Whether Darcy’s law remains valid for non-uniform fluid flow having varying cross sectional area?

Even with radial flow, how about the flow analysis with wellbore storage and boundary effects?

8. Whether Darcy’s law be applied in the vicinity of injection or production well, where, the stream lines become curvilinear?

9. Whether Darcy’s law be applied to a reservoir, where, the well is not drilled to the entire thickness of the reservoir?

10.                  Whether Darcy’s be applied to a reservoir that includes reservoir thermodynamics (phase changes associated with temperature/pressure variation: non-isothermal conditions) as well, on top of considering reservoir fluid dynamics?

11.                  Can Darcy’s law take into account any pore-scale detail?

Then, what is the very purpose of applying continuum-scale using the concept of REV?

12.                  Can Darcy’s law explicitly take into account capillary (IFT) and wettability (contact angle) effects?

Does Darcy’s law take into account fluid-fluid interaction and fluid-solid interaction?

13.                  Can Darcy’s be applied for a fluid system having a significant and varying compressibility?

14.                  What was the need for Darcy to deduce an explicit equivalent momentum conservation equation – for characterizing fluid flow through a porous medium - than directly applying Navier-Stokes equation?

Suresh Kumar Govindarajan

Professor (HAG)    IIT Madras

https://home.iitm.ac.in/gskumar/

https://iitm.irins.org/profile/61643 26-July-2024

In nanofluids, surfactants play a great role in stability. What is the impact of surfactant in viscosity in nanofluids? If surfactant concentration increases, then viscosity will increase/decrease and why/

I tried to make slurry for NCM cathode but there was problem in coating process. The detail of my experiment is following;

The ratio between active material(NCM811), conductive additives(Super-P) and PVDF is 80:10:10. PVDF was dissiolved in NMP and ratio was 5w%

Then I mixed them by plentary mixer with 2000rpm for 2 times. First mixing was conducted for 5min and second minixing time was 10 min.

Finally I coated it on Al foil with 300, 350, 400 micrometer by doctor blade.

The humidity was high due to heavy rain at that time. I think humidity makes viscosity of slurry high. But I don't understand why slurry isnt coated well in the middle of foil while near starting point and ending point showed quite good coating.

Hi everyone,

I try to do a simulation about heat transfer of supercritical hydrogen in a cooling channel. Properties of H2 is obtained from NIST and displayed by an UDF function. I used the k-w model. If i set inlet temperature at 300K, everything is fine and correct. But when i set it to 34.6K, i ran into the problem " turbulent viscosity limited to viscosity ratio of 1.000000e+05 in xxx cells". My mesh is very fine as displayed below. CAn anyone help me to solve the problem

I have tried combination of few monomers and resulting emulsion shows tack but tack is not enough to be measured by lap shear test machine, should I try new combinations or use some other method to check adhesion? by changing ratios of monomers viscosity is getting higher with formation of lumps

is there any accurate method to calculate the thermophysical properties of water- surfactant mixtures, including thermal conductivity, specific heat, boiling point, surface tension, viscosity ?

I am trying to run a turbulent pipe flow simulation with turbulent Reynolds number of 600, for 15 seconds, the flow is pressure driven due to gravity enforced buoyancy force which gives kinematic viscosity input as 8.25E-0.5 N/m^2, if gravity value taken as 9.81.

But in this case the flow is unable to become turbulent for smagorinsky LES model. Is this because of the high viscosity input? because for same inputs and changing Re = 2400 and \nu = 2.06E-05 the flow starts to become turbulent within the span of 15 seconds.

1. to make my simulation run changing gravity value and keeping the nu = 2.06e-05 to obtain same Re = 600 will be a solution's to this?? (I'm trying to check this with trial runs)

2. Why does this happen? any physical intuitions for this kinda behavior with \nu values ??

I do the rheological experiment on ZnTiO3 sol-gel.

I am not able to get the theoretical extract of how viscosity properties change with time of this sol-gel of ZnTiO3.

Hi all,

I am trying to conduct Dynamic Light scattering experiments on polymer sample using Malvern Zetasizer ZS. One question I have is to whether it is okay to use complex viscosity instead of normal viscosity while preparing the SOP for the experiment?

Thank you,

Richa Ghosh

What is the typical viscosity range for ceramic pastes used for the Direct Ink Writing (extrusion) process? I have read several articles, and all give different figures; I saw somewhere else that between 20 Pa.s and 50 Pa.s is ideal. What is your answer to this?

Pva

According to the "chauveteau 1981" article, the apparent viscosity decreases at low shear rate and then increases after a critical shear rate.

He didn't mention how to calculate the apparent viscosity and its equation ,,,

If anyone has experience in this respect please help me.

Dear Readers,

I am writing to request assistance in obtaining numeric or number format data related to turbulent flow in ducts, specifically focusing on square, rectangular, and other geometries. I require data for cases of steady, fully developed flow in the cross section of the duct, with a particular interest in cross-sectional details.

The data I am seeking should be presented in a format that includes the following parameters:

- Horizontal coordinate (x2)

- Vertical coordinate (x3)

- Flow properties: main velocity (U), secondary velocities (V and W), turbulent kinetic energy (K), turbulent viscosity, turbulence dissipation rate (e), turbulent stresses (shear and normal), pressure distribution in the cross section, boundary shear stress, and flow parameters (longitudinal pressure gradients, duct geometry dimensions, friction factor, fluid density and viscosity, wall roughness conditions, etc.).

I have come across several articles that contain relevant information, but the data is presented in graphical form, making it challenging to extract the specific numeric values. Therefore, I kindly request your assistance in providing the data in numeric or number format, as described above.

Examples of experimental data sources include:

- Leutheusser, H.J. 1963. "Turbulent flow in rectangular ducts." J. Hydr. Div. ASCE 89 (3), 1–19.

- Brundrett, E., Baines, W. D. 1964. "The Production and Diffusion of Vorticity in Duct Flow." J. Fluid Mech., 19 (3), pp. 375-394.

- Gessner, F. B., Jones, J. B. 1965. "On Some Aspects of Fully-Developed Turbulent Flow in Rectangular Channels." J. Fluid Mech., 23 (4), pp. 689-713.

- Gessner, F. B. 1973. "The Origin of Secondary Flow in Turbulent Flow along a Corner." J. Fluid Mech., 58 (1), pp. 1-25.

- Melling, A., and Whitelaw, J.H. 1976. "Turbulent flow in a rectangular duct." J. Fluid Mech. 78, 289.

- Gessner and Emery. 1980. [Additional information needed]

- Leutheusser, H. J. 1984. "Velocity distribution and skin friction resistance in rectangular ducts." J. Wind Eng. Ind. Aero. 16, 315–327.

- Thangam, S., Speziale, C. G. 1987. "Non-Newtonian Secondary Flows in Ducts of Rectangular Cross-Section." Acta Mech., 68 (3-4), pp. 121-138.

- Rokni, M., et al. 1998. "Numerical and Experimental Investigation of Turbulent Flow in a Rectangular Duct." Int. J. Numer. Meth. Fluids, 28 (2), pp. 225-242.

Additionally, I am interested in numeric data, such as numerical predictions and Direct Numerical Simulation (DNS) data, from studies conducted by Naot and Rodi (1982) and Demuren and Rodi (1984):

- Naot, D.; Rodi, W. 1982. "Calculation of secondary currents in channel flow." ASCE J. Hydraul. Div. 108, 948–968.

- Demuren, A.O.; Rodi, W. 1984. "Calculation of turbulence driven secondary motion in noncircular ducts." J. Fluid Mech. 140, 189–222.

Furthermore, if any numeric data is available for other flow types, such as flow in cavities, flow at backward-facing steps, flow around cylinders, and flow around square rods, it would be greatly appreciated.

Thank you in advance for your assistance and contributions toward fulfilling this request. Your support will significantly contribute to the advancement of turbulent flow research.

Sincerely and best Regards,

Since intrinsic viscosity show a relationship with molecular weight of Polymer. So, how about solid content? Does solid content show us about any polymer properties? Like particle size maybe?

This because, I'm doing my research for synthesis homopolymer acrylic sodium salt (MW 2000 - 3000) and always getting more than 45% whereas my target is 40 - 42%

I am using TfOH, DMC, dimethyldimethoxysilane and MM as the starting material, I have tried to reduce the amount of MM, but I constantly obtained low viscosity silicone oil (~100 mPa`s). I once obtained a 1000 mPa's but this reaction cannot be repeated. Could someone please give some advice. many thanks in advance

How can I determine the molecular weight of a polysaccharide (as a powder) dependng on the viscosity?

Ways to determine the chemical properties of mixture of fluids at different composition's and different temperatures using different various formulas.

The chemical properties involve

Desnity,viscosity,velocity,thermal conductvity and other

This is a code block from nutWallFunction library in OpenFOAM where in, effective kinematic viscosity ($\nut_w$) at the wall is calculated using resolved field(in case of LES)/ mean field(in case of RANS) and $y^+_p$ (wall normal distance of the first cell center). this allows to set a new viscosity value as boundary condition at the wall using log law. Considering the first cell center is in the logarithmic layer of the universal velocity profile.

Now, in this code block of member function defined as nutUWallFunctionFvPatchScalarField::calcYPlus()

There has been iterations done for the yPlus value to reach convergence with maximum of 10 iterations. Why are these iterations needed? and why is the maximum number of iterations 10. I have given a reference of the code below;

tmp<scalarField> nutUWallFunctionFvPatchScalarField::calcYPlus

(

const scalarField& magUp

) const

{

const label patchi = patch().index();

const turbulenceModel& turbModel = db().lookupObject<turbulenceModel>

(

IOobject::groupName

(

turbulenceModel::propertiesName,

internalField().group()

)

);

const scalarField& y = turbModel.y()[patchi];

const tmp<scalarField> tnuw = turbModel.nu(patchi);

const scalarField& nuw = tnuw();

tmp<scalarField> tyPlus(new scalarField(patch().size(), 0.0));

scalarField& yPlus = tyPlus.ref();

forAll(yPlus, facei)

{

scalar kappaRe = kappa_*magUp[facei]*y[facei]/nuw[facei];

scalar yp = yPlusLam_;

scalar ryPlusLam = 1.0/yp;

int iter = 0;

scalar yPlusLast = 0.0;

do

{

yPlusLast = yp;

yp = (kappaRe + yp)/(1.0 + log(E_*yp));

} while (mag(ryPlusLam*(yp - yPlusLast)) > 0.01 && ++iter < 10 );

yPlus[facei] = max(0.0, yp);

}

return tyPlus;

}

My doubt is concerning the do-while loop at the end for yPlus iteration.

I am not an expert in rheology and I have some questions.

I have two different brands of viscometers, a Thermo Electron Viscotester E-L and a Brookfield DV-II+Pro. I can not get the same result with the LV-4 spindle on the Thermo device with the spindle no 64 on the Brookfield device. Theoretically, I know that these two spindles are the same geometry. (Am I wrong?)

In the Brookfield device manual say" When viscosity data must be compared, be sure to use the same test methodology: namely the same instrument, spindle, speed, container, temperature and test time.". One of the results is 30k while the other is around 70k. However, I did not expect a big difference between the two devices. The only thing that comes to my mind is that "Brookfield dsoes not recommend the use of these spindles (LV #4) to perform a calibration check on your instrument. Reasons pertain to the small amount of spindle surface that makes contact with the viscosity standard, the difficulty of establishing the immersion mark precisely and the need for precise temperature control at 25°C in the immediate vicinity of the spindle." mentioned in the device manual.

How do I know which result is correct?

I am trying to purify a cell lysate using a 1 mL His-trap column but the viscosity of the lysate is clogging up the column. What are some solutions to this?

Harrison, Sykes and Matins article «Wave effects in Insulation Mounts» in JASA from feb 1952 give models and measurement results for vibration insulation transfer curves showing more than one resonance.

I think I saw that reference in a more recent paper by Charlotte Crispin on floating floor models along with with more modern calculation methodes.

Harrison et al use two terms for viscosity, longtudinal viscosity and a shear viscosity of the vibration insulating material, assumed to be a kind of rubber. They appear to have high expertise in material properties and may have measured these in their lab on their own.

However, regular «googling» only have lead to data for extrusion of rubber, that is as hot melted material and not as dry cold dampers

I am used to work with the loss factor, or any damping parameter, as a part of the vibration insulation, and assume the viscosities relates to damping or losses in some form. It seem as if the «damping» is frequency dependant. For a standard vicous damping model the used damping term is usually a frequency independant constant.

I would be very interested in sources for shear viscosity data for damping materials, or a guide to theory or literature that shed light on this. Or a method to measure it.

Multi-Phase Fluid Flow

1. If varieties of macro-flow characteristics can be formed in the process of two-phase displacement, resulting from the interface instability of displacement front, whether, would it remain feasible to capture the instability of displacement front @ laboratory-scale using experiments, which remains controlled by the competition between capillary forces @ pore-scale; and non-local viscous forces @ Darcy-scale, in the absence of gravitational forces?

OR

The influence of various flow conditions and physical properties (wettability, geometric topology and surface roughness) related to the reservoir rock formation, make this competition between capillary and viscous forces to remain to be more complicated to be captured?

If it remains to be complicated, then, can’t we directly quantify such competition between capillary and viscous forces using only Capillary Number and Viscosity Ratio?

Is it because capturing the characteristic velocity of the invading phase remains to be challenging @ laboratory-scale?

2. How exactly to ensure the following @ field-scale?

(a) Under the condition of unfavorable viscosity ratio, as the Capillary number increases, the viscous forces would gradually tend to dominate, while the displacement pattern gradually transitions from capillary fingering to viscous fingering; and

(b) Under the condition of favorable viscosity ratio, the displacement pattern changes from capillary fingering to stable displacement upon increasing the Capillary number; and

(c) Feasible to capture the transition zone between different displacement patterns (crossover zone) @ field-scale?

Does this transition (changing Capillary number and viscosity ratio to change the displacement pattern) consider the influence of wettability?

Or

Is it only applicable to the drainage process of non-wetting phase displacing wetting-phase?

If the influence of wettability on fluid displacement remains included, then, how will we be able to capture the series of pore-scale reconstruction events (i.e., contact, overlap and burst) and its associated displacement patterns at various Capillary numbers, @ laboratory-scale using experiments?

If yes, then, how precisely will we be able to capture the following?

(a) Feasible to capture the characteristic of capillary fingering @ laboratory-scale, when burst instability mechanism remains dominant (when the displaced phase wets the pore wall more; and the contact angle remaining greater than 90 degrees: drainage)?

(b) Feasible to capture, the way, the interface of the displacement gets stabilized and promoting the compact displacement of immiscible fluids, when the invading-phase wets the wall more (and the contact angle remaining lesser than 90 degrees: imbibition) with the frequency of contact and overlap mechanisms remaining higher?

(c) the way, the fluid displacement process getting gradually transitioned from dominant capillary forces to dominant viscous forces (the role of viscous forces getting gradually increased) with the increase in flow velocity?

How can you gel or increase viscosity of a trichloroacetic acid solution?

It seems carbomer and Na-CMC are degraded rapidly by the very acidic TCA, while HPMC drops out of solution at higher TCA concentrations. I did measure a pH of -1.5, so that is rather hefty!

As shown in the photo, the curved mandrel must be immersed in liquid TPU through a dip molding process.

However, the outside of the bent part will always be thinly coated.

Can you tell me the reason for this and how to solve it?

TPU has a high viscosity of 30,000 cps.

Thanks you.

I`m trying to prepare a solution of water-cmc with the highest content of CMC possible for further processing, but I wanted to know how I can lower the viscosity so it will be easier to handle but still dissolve properly?

Thanks

Can we partly cure Butyl rubber sealant formulation at room temperature in 10-15 days time. The purpose of adding a curing system in the formulation is to add the tensile in the product without any degradation and to minimize the loss of Mooney viscosity at the elevated temperature.

I want to check the viscosity of the non-Newtonian fluid using an Ostwald viscometer.

I'm trying to measure changes in the molecular weight of treated polyethylene, I found that using dilutions in an organic solvent of the sample on a capillary U-tube viscometer to determine the intrinsic viscosity and from there use Mark–Houwink–Sakurada Equation to determine molecular weight the is the way to proceed, exists another method to do it?

I want to study the viscosity of the of ferrofluids. Would anyone please suggest me institutes in India where I can do magneto rheology studies ?

Hello to all

Does anyone have reliable information about the chemical properties of methanol and the combination of methanol with water?

With valid reference

We need this information to select the material for the pump

Information like

viscosity

density

ph

...

Is the formula for calculating the viscosity of non-Newtonian fluids the same as Newtonian fluids?

Hi everyone. Greetings to you all.

Recently, I tested the viscosity of the epoxy resin and CF/epoxy prepreg samples using a TA-discoveryHR-1 rheometer.

Firstly, in an isothermal way(holding temperature at 180℃), I want to study Viscosity vs Holding time.

Secondly, in a temperature-ramping way (rising temperature from 50℃ to 180℃), I want to study Viscosity vs Temperature.

However, I have two types of samples: epoxy and CF/epoxy prepreg. Note that Some micro-sized particles are dispersed in epoxy.

Due to my poor experiences, I don't know how to choose the rheology test mode (flow mode or oscillation mode?) Some preliminary results of viscosity looked weird.

So my questions are as follows:

Q1) In an isothermal way(holding at 180℃), when I test the viscosity of epoxy, which testing mode (Flow or oscillation) is better?

Q2) In an isothermal way(holding at 180℃), when I test the viscosity of CF/epoxy prepreg, which testing mode (Flow or oscillation) is better?

Q3) In a temperature ramping way(50℃→180℃), when I test the viscosity of epoxy, which testing mode (Flow or oscillation) is better?

Q4) In a temperature ramping way(50℃→180℃), when I test the viscosity of CF/epoxy prepreg, which testing mode (Flow or oscillation) is better?

If you could share some of your experiences with rheometer testing epoxy-related samples, I would be grateful for your kindness.

Thank you for reading.

Best wishes!

I have seen indications of the use of candle filters and bed filters for hot vapour filtration of bio-oil, but never liquid phase.

Is this solely due to viscosity and fouling or is additional degradation seen when liquid phase filtration is used?

Is this also the case for aqueous washes of bio-oils?

How can I derive polynomial functions that can predict the viscosities of pure liquid water in function of temperature at atmospheric pressure? I used experimental data from literature, but the equation that I derived by using Excel but after derived the equation when I putted the value of temperature (independent variable), it's not worked!

I have plots of shear stress vs shear rate and viscosity vs shear rate. I want to check which rheological model do my systems (hydrogels) follow and calculate the parameters form the best fitting model. Can anyone give me idea on how to perform this analysis? Thanks a lot

I am using 4000 cP methyl cellulose for aqueous tape casting. Since it gives very viscous solution, I am dissolving it in 1.5 wt% in 98.5 wt% DI water. Still it is a very viscous solution. Because of a large quantity of inherent water coming from the MC binder solution, I cannot use more than 1 wt% binder active matter w.r.t powder in slurry, otherwise the powder settles down on container base and water floats on top and there is no mixing because of a lot of water.

What MC viscosity is better keeping in mind a higher possible weight percent dissolution in water? And in how much weightage should it be dissolved in water and at what temperature?

Since sedimentation of particles is very high, what do you recommend for usage of such sized particles for making a good slurry?

Sarbaev, A. N.; Polyakov, E. V.; Ruchkova, A. Kh. Density, viscosity and elecrical conductivity of aqueous monoammoniumphosfate Zh. Prikl. Khim., 1972, 45, 2749-2751 T = 293.15 to 353.13 K P = 101.00 to 101.00 kPa

I use a DWS System's DS3000, a photosensitive monomer to disperse the nanoparticles in it and use the solution for SLA printing. But, because of its high viscosity, I cannot increase the particle concentration, which is my goal.

In his book: "FUNDAMENTAL PRINCIPLES OF POLYMERIC MATERIALS", Third Edition, 2012, Wiley, the authors Brazel & Rosen wrote, page 274, problem 14.18: "Note: The fluid is pseudoplastic, but not power law.". What is the key to explain it? I know that there is Non-newtonian fluids, like Bingham, Casson, Herschel-Bulkley with yield stress value, which can not be described by power-law (Ostwald de-Waelle) model. I also know about Cross, Carreau, and other rheological models, with zero shear viscosity, infinite shear viscosity, etc. But, in the context of the problem proposed by the authors, what is the limitation, or, in other words: what is the implication of a fluid that is shear thinning (at least in some intermediate region of shear rate), but that cannot be described by the power-law model? What difference does this make to pipe sizing to ensure laminar flow?

For example, it is well known that the viscosity of the fluid changes, but does it change in the same relationship if CO2 is miscible or if it is immiscible? Or maybe there are properties that are more affected in a case such as solubility, capillary pressure, and relative permeability?

When using the dimatix samba cartridge, can it be used even if the viscosity of the fluid is less than 4cp?

The ideal requirement is 4-8cp, but has anyone tried using a fluid lower than that?

Hello. I need to 100 ul from 75mg/ml polyethyleneimine solution (M.N. 60000 and 50 wt.% aqueous solution). Its a very viscose liquid and with CAS No [9002-98-6].

I have 3 challenges:

1-what is M.N 60000?

2-How much is PEI density?

3-How can I aspirate PEI solution with a micropipette? Do I have to heat PEI?

Thank you for taking time.

in suspension, how to reduce the viscosity caused by xanthan gum?

I took into account the viscosity of the water at 25°C (0.89 cP)

I would like to know how the well-dispersed nanoparticles within a polymer would increase the viscosity of the resulting product (i.e., the polymer nanocomposite)?

I am trying to model a process in which there is a flow of non-newtonian Herschel-Bulkley fluid. to derive equations of pressure drop, wall shear stress and drag force(for spheres inside the fluid) i need a form of reynolds number for herschel bulkley fluids.reynolds number should consider existence of yield stress in rheogram of fluid.

so is there any generalized form of Reynolds number that is applicable for herschel-Bulkley fluids??

I surveyed previous works but i didn't finds so much about

Where can I find data about viscosity dependence on concentration in methanol–poly(vinyl acetate) solution? What value of saturation concentration and diffusion coefficient for the solved polymer in this solution at room temperature?

Dear researchers,

"From below Figure, the extensional viscosity estimated from CaBER (Capillary breakup extensional rheometer) is too apparent, not true rheological data".

What do you think about this statement?

- In my opinion, a capillary rheometer is an apparatus designed to measure shear viscosity and other rheological (= flow) properties such as extensional viscosity, extrudate swell, thermal stability, wall slip. So the data showed in this Fig is the rheological data. I am not sure about above statement. Please give some advice.

Thank you very much.

hello evryone,

when a polymer has a narrow( fig below) distribution, the macromolecules don't flow in the same way, so this will impact the polymer's viscosity, which can lead to extrusion distortion.

On the other hand, if the polymer's distribution is wide( fig below), there is consistency in the viscosity, so the orange skin ( fig below) effect is hardly noticeable. is it true ?

Hi, I am looking to conduct rheometric experiments on water or hydrogels whose viscosity is very less. Should I use Dynamic light scattering or a rheometer?

Is it possible to create a 100-um thick polyimide layer through spin coating? If possible, What will the pi liquid's spin speed and viscosity?