Energy Of Viscous Flow Research Articles

Densities and viscosities of (ethylene glycol - water) and (1,3-propanediol - water) binary mixtures at high temperatures of 373.2 and 473.2 K and high pressures up to 40 MPa

Densities and viscosities of ethylene glycol - water and 1,3-propanediol - water binary mixtures have been measured over the whole composition range at 373.2 K and 473.2 K and at pressures up to 40 MPa. The excess molar volumes combined with partial molar volumes, and viscosity deviations have been calculated from the measurement data. The activation Gibbs free energy of viscous flow has been also evaluated from the density and viscosity data. These results were compared with the previously reported results of the monohydric alcohol - water mixtures with the same carbon numbers to discuss the effect of hydroxyl group and alkyl chain length on these properties in the wide range of temperature and pressure. The physical properties of the alcohol - water mixtures were strongly influenced by the molecular structure of the alcohol molecules under the studied conditions. In particular, the excess molar volumes and viscosity deviations showed very different behaviors for monohydric and dihydric alcohol - water mixtures.

Evaluating the Effect of MgO/Al2O3 Ratio on Thermal Behaviors and Structures of Blast Furnace Slag with Low Carbon Consumption

In order to clarify the effect of the MgO/Al2O3 ratio on the fluidity of a low-alumina blast furnace slag system, the influence law of slag fluidity with different MgO/Al2O3 ratios was studied based on the composition of blast furnace slag through a viscosity experiment and themodynamic software. By studying the effect of the MgO/Al2O3 ratio on the activation energy of viscous flow of slag combined with FT-IR, the effect of the MgO/Al2O3 ratio on the thermal-stability of low-aluminum slag was interpreted from the microstructure level. Results indicated that the viscosity and the melting temperature of slag both showed a gradual downward trend due to the increase of the MgO/Al2O3 ratio. Besides, the temperature stability of the low aluminum slag became more stable due to the depolymerization of the complex structure of slag. Considering the actual operating conditions of blast furnace, the MgO/Al2O3 ratio of slag was suggested to be controlled to 0.60 and the basicity to be no higher than 1.20 under the conditions of this investigation. Industrial test results showed that the coke rate could be saved as 3.49 kg/t when the MgO/Al2O3 ratio decreased from 0.70 to 0.58.

A rational synthetic approach for producing quaternary ammonium halides and physical properties of the room temperature ionic liquids obtained by this way

In the present paper the rational strategy for the high-yield solvent free synthesis of alkylammonium halides which consists in the nucleophilic addition of alkylaminoethanols to 2-chloroethanol was described. The proposed strategy was used to synthesize hydroxyl-functionalized solid ionic compounds such as dimethyl (or methyl) di-(tri)(2-hydroxyethyl) ammonium chloride and tetra-(2-hydroxyethyl) ammonium chloride, as well as novel room temperature ionic liquids (RTILs) such as dimethyl (IL-4) and methyl mono-(di-)(2-hydroxyethyl) (2-hydroxyethoxy)ethyl chloride (IL-5) all of which were characterized by FT-IR, 1H and 13C NMR. For the newly obtained RTILs, density (ρ) and viscosity (η) were obtained at temperatures from T = (283.15 to 353.15) K while the refractive index (nD) was measured from T = (283.15 to 343.15) K. The data on ρ and nD were used for calculation of the RTILs’ fractional free volumes (FFV), molar refraction, and pseudo-activation energy of viscous flow. In addition, NH3 absorption capacity of the obtained ILs was estimated gravimetrically. It was shown that this property correlates with the IL’s FFV and increases by two times for IL-5 which exhibits an additional hydroxyl group compared to IL-4.

Development of natural deep eutectic solvents (NADESs) as anti-freezing agents for the frozen food industry: Water-tailoring effects, anti-freezing mechanisms and applications

Nature-inspired natural deep eutectic solvents (NADESs) as anti-freezing agents including Pro:Glc (5:3), Pro:Glc (1:1), Pro:Sor (1:1), and Urea:Glc:CaCl2 (3:6:1) were prepared. Viscosity (η), conductivity (σ), activation energy of viscous flow (Eη) and conduction (Eᴧ), transverse relaxation time (T2), thermal behaviours, and anti-freezing capacities of the NADESs were investigated. A critical T2 of 24.60 ms for η changes was obtained, and the relationship between η and T2 was determined as lnη = -1.398lnT2 + 10.688. Differentialscanningcalorimetry and low-field nuclear magnetic resonance analyses indicated NADESs could hinder the molecular motion as temperature decreased through enhancing the hydrogen-bonding strength, endowing them with excellent anti-freezing capacity. NADESs showed varied Eη (41.58 ∼ 45.72 kJ mol−1) and Eᴧ (48.31 ∼ 63.08 kJ mol−1), of which Pro:Sor (1:1) possessed the greatest ones, showing its greatest temperature sensitivity and best anti-frosting capacity. Applications in frozen chicken breast further announced the potentials of NADESs as anti-freezing agents for the industry.

Viscosity of silica and doped silica melts: evidence for a crossover temperature

AbstractSilica is known as the archetypal strong liquid, exhibiting an Arrhenius viscosity curve with a high glass transition temperature and constant activation energy. However, given the ideally isostatic nature of the silica network, the presence of even a small concentration of defects can lead to a significant decrease in both the glass transition temperature and activation energy for viscous flow. To understand the impact of trace level dopants on the viscosity of silica, we measure the viscosity‐temperature curves for seven silica glass samples having different impurities, including four natural and three synthetic samples. Depending on the type of dopant, the glass transition temperature can vary by nearly 300 K. A common crossover is found for all viscosity curves around ~2200–2500 K, which we attribute to a change of the transport mechanism in the melt from being dominated by intrinsic defects at high temperature to dopant‐induced defects at low temperatures.

Relationship between Kinematic Viscosity and Cluster Size in Multicomponent Metal Melts

We analyzed the temperature dependences of the kinematic viscosity and density of Fe73.5Cu1M3Si13.5B9 melts, where M = Nb, Mo, V, and Cr, in the temperature range from 1450 to 1950 K using the transition state theory. It is shown that the activation energy of viscous flow is proportional to the particle size on a natural logarithmic scale. The lowest viscosity and the highest free volume has the Nb melt. In melts with Mo, V, and Cr, the structural units of viscous flow upon heating and cooling are clusters about 0.6 nm in size. In a melt with Nb, at the initial stage of heating, the vibrations of individual atoms prevail, the movement of which creates viscosity. After heating the Nb melt above the critical temperature of 1770 K, the viscous flow is associated with clusters about 1 nm in size. At the cooling stage, the cluster structure of the Nb melt is retained up to a temperature of 1450 K.

The effect of TiO2 on the thermal stability and structure of high acidity slag for mineral wool production

In order to promote the application of Ti-bearing blast furnace slag in mineral wool manufacture, the viscosity, thermal stability and structure of melt were studied in this paper. And the concept of “Extreme Heat Release of Slag (EHRS)” was firstly proposed to quantify the thermal stability of melt. The results showed that slag viscosity decreased with the increase of TiO2 content in the range of 0wt% to 6wt% at acidity coefficient (Mk) of 1.0~1.6. TiO2 reduced the heat capacity of melt, but increased the EHRS. And when the Mk was 1.3, the EHRS was relatively large. The variation of activation energy of viscous flow had a good agreement with that of viscosity. In addition, TiO2 acted as network modifier in the melts, which decreased the average number of bridging oxygens from 2.93 to 2.71. Ti4+ mainly existed in the form of [TiO4] 4– monomers and O–Ti–O in chain or sheet units, resulting in the decrement of slag stability. At the Mk of 1.3, increasing TiO2 content to 6wt% would beneficial for the production of fibers with uniform diameter and length.

Life at low Reynolds Number Re-visited: The apparent activation energy of viscous flow in sea water

In a 1976 lecture entitled “Life at low Reynolds Number,” Edward Purcell examined constraints on mobility of small aquatic animals defining the energetic challenge as “to move far enough to beat diffusion.” We show that the essential requirement is the need to do sufficient work to overcome the activation energy of viscous flow. Raman spectroscopy shows that sea water is dominated (78–85%) by the hydrogen bonded forms, primarily as the large (H2O)5 tetrahedral pentamer form. Two hydrogen bonds must be broken to disrupt this structure. The strength of the hydrogen bond in water is ~8.4 kJ/mol and the experimentally determined activation energy of viscous flow (~16.7 kJ/mol) is approximately equal to that required to break two hydrogen bonds in water. For viscous flow to occur a molecular vacancy must form for a flowing molecule to move into; the smaller the vacancy needed the less energy required. The heat created by a small animal swimming breaks hydrogen bonds thus forming a layer of small non-hydrogen bonded H2O molecules around the animal. These “lubricate” the surface yielding far more efficient viscous flow. The activation energy of the viscous flow of water decreases with pressure most likely due to the weaker strength of the hydrogen bond under pressure – lab and field data support this observation. The dissipation of tidal energy as heat, often attributed to “intermolecular forces,” is directly related to the breaking of hydrogen bonds.

Effect of Physical Fields on Highly Resinous Oil

This paper studies the effect of physical fields (i.e. ultrasonic and constant magnetic fields) on structural and energy properties (viscosity, limiting shear stress, pour point, activation energy of viscous flow) as well as kinetic (antioxidant) properties of highly resinous problematic oil. The results were obtained via viscometry, determining of pour point and voltammetric method of oxygen electroreduction. It was shown that the treatment of studied oil by acoustic and magnetic fields lead to decrease in viscosity and temperature parameters. Combined treatment displays an additional reduction of viscosity and pour point

Effect of MnO and CaO substitution for BaO on the viscosity and structure of CaO-SiO2-MgO-Al2O3-BaO-MnO slag

The effect of MnO and CaO substitution for BaO on the viscosity and structure of CaO-SiO2-MgO-Al2O3-BaO-MnO slag was investigated using the rotating cylinder method and the structure was analyzed by employing FT-IR and XPS. The results showed that the viscosity at various temperatures decreased gradually when MnO content increased from 0wt% to 3wt%, and increased with BaO content rising from 0wt% to 5wt%, which was consistent with the corrected optical basicity (Λcorr). The activation energy for viscous flow (Eη) showed the similar trend. FT-IR and XPS spectra analysis indicated that both [SiO4]-tetrahedral and [AlO4]-tetrahedral were influenced by MnO and BaO content. The [SiO4]-tetrahedral and [AlO4]-tetrahedral network structures were depolymerized due to an increase in the relative fraction of free oxygen (O2−) and decrease of bridging oxygen (O0) with the increasing MnO content. As a larger amount of CaO was substituted by BaO, the trough depth of [SiO4]-tetrahedral and [AlO4]-tetrahedral bands became deeper, indicating the complexity of network structure and polymerization degree of slag increased, which led to an increase in viscosity.

Performance analysis and comparison of methyl-modified Al2O3/SiO2 xerogels fabricated by two methods

Abstract Two methyl-modified Al2O3/SiO2 xerogels, i. e. AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels, were prepared using aluminum isopropoxide and aluminum nitrate nonahydrate as the aluminum precursors, respectively. The appearance, density, viscosity, Gibbs activation energy for viscous flow and reaction rate constant of the sols were analyzed and compared. Their microstructures were characterized by means of powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and nitrogen adsorption–desorption measurements. The results show that the Al–O–Si bond is formed in the AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels. The ANN-Al2O3/MSiO2 sol has a smaller mean particle size and greater sol stability than the AIP-Al2O3/MSiO2 sol. Meanwhile, the ANN-Al2O3/MSiO2 xerogel has a smaller pore size and higher porosity. The total pore volume and specific surface area of the ANN-Al2O3/MSiO2 xerogel are 27.27% and 29.36% larger than those of the AIP-Al2O3/ MSiO2 sample, respectively. The saturated adsorption capacity of the ANN-Al2O3/MSiO2 xerogel to methylene blue is 7.15% larger than that of the AIP-Al2O3/MSiO2 xerogel.

Physicochemical studies on vitamins B1, B3, B6 and C in aqueous magnesium chloride solutions at different temperatures (288.15–318.15) K and at pressure (101.3) kPa

Vitamins are the precursors of many coenzymes essential for biocatalysts and their deficiency leads to diseases in masses. The vitamins are very fragile and can easily be destroyed with change external atmosphere. Electrolytes are inherent constituents of cytoplasm and are required in variety of biochemical functions. The interactions occurring between, solute-cosolute and solvent can be inferenced and interpreted from thermodynamic and transport studies effectively which will help in interpreting the mechanism of vitamins in solution phase. In the present study apparent molar volume ϕV, and viscosity B-coefficient B, have been determined for l-ascorbic acid (Vit.C), nicotinic acid (Vit.B3), thiamine hydrochloride (HCl salt of Vit. B1) and pyridoxine hydrochloride (HCl salt of Vit. B6) in aqueous magnesium chloride solutions (mB = 0.1 to 0.5 mol∙kg−1) over the temperature range (288.15–318.15) K at pressure (101.3) kPa. The partial molar volume of transfer, ∆trϕVo, and viscosity B-coefficient of transfer, ∆trB, for these compounds from water to aqueous solutions of magnesium chloride have been determined from the corresponding data. First (∂ϕVo/ ∂T) P and second (∂2ϕVo/ ∂T2)P, derivative of ϕVo and dB/dT, values have been calculated. B/ϕVo ratio, activation free energy of viscous flow of vitamins ∆μ2o#, and other parameters have also been calculated. Both volumetric and viscometric studies suggest the presence of complex interactions at lower concentrations, but the role of cosolute becomes decisive at higher concentrations. The dB/dT values and activation parameters (∆S2o#, ∆H2o#) values suggest that l-ascorbic acid, thiamine hydrochloride and pyridoxine hydrochloride show bond making tendencies with magnesium chloride while nicotinic acid shows comparatively less affinity with magnesium chloride.

Temperature-Dependent Rheological Behaviors of Binary Eutectic Mixtures of Sugar Alcohols for Latent Heat Storage: A Comparative Study with Pure Sugar Alcohols

The temperature-dependent rheological behaviors of five selected binary eutectic mixture sugar alcohols, with great potential for latent heat storage in the range of 353.15 K to 523.15 K, were investigated. It was found that the rheological behaviors of the mixture sugar alcohols depend on those of the pure compounds as well as their molar ratios. The two mixtures of xylitol (75 mol%)+erythritol and erythritol (84 mol%)+d-mannitol behave like pseudoplastic fluids with typical non-Newtonian shear-thinning behaviors, as indicated by the power law index of 0.99 (<1). The mixture of d-mannitol (70 mol%)+d-dulcitol is a nonlinear Bingham fluid, exhibiting a slight yield stress (0.001 Pa to 0.01 Pa) at low shear rates. The rest two mixtures containing the cyclic-structured inositol behave like Herschel-Bulkley fluids. The infinite shear viscosities of the eutectic mixtures over the entire temperature range appear to be higher than those of their respective pure compounds, except for inositol. The mixture of xylitol (75 mol%)+erythritol at its melting point shows higher dynamic viscosity of about 0.546 Pa·s than the values of about 0.396 Pa·s and 0.035 Pa·s for xylitol and erythritol, respectively. In addition, the activation energies of viscous flow of the mixtures, as determined by fitting the dynamic viscosity-temperature curves using the Arrhenius model, also exhibit higher values than those of their pure compounds. The activation energy of viscous flow of the mixture xylitol (75 mol%)+erythritol was determined to be about 92 400 J/mol in the supercooled liquid state, while the supercooled liquid xylitol and erythritol have much lower values of 83 500 J/mol and 51 900 J/mol, respectively. Both the increased dynamic viscosities and activation energies of viscous flow can result in deteriorated crystallization performance during latent heat retrieval.

Dynamic viscosity dependence on temperature for fuels used for diesel engine

Abstract Viscosity is an important property of fuels used for diesel engine affecting engine’s efficiency and harmful gases emission. Viscosity of liquid fuels depends especially on fuels composition and temperature. The dynamic viscosity of diesel fuel, biodiesel and blends of diesel with biodiesel, i-propanol and n-butanol was measured for temperature ranging from 293.15 K to 323.15 K and atmospheric pressure. It has been verified that well-known Arrhenius derived equations can be used to estimate with good accuracy, viscosity at different temperatures for diesel, biodiesel, diesel+biodiesel blends, but also for diesel blends with propanol and butanol. Values of activation parameters: activation energy, activation enthalpy and activation entropy for the viscous flow were derived based on linearized Eyring’s type equation. The values of the activation energy for viscous flow of fuels and fuels blends calculated based on measured values of dynamic viscosity in the temperature range of 273.15 K and 323.15 K were similar to those presented in the literature for some hydrocarbons, esters, and alcohols, respectively.

ENTROPY INFLUENCE ON THE DEPENDENCE OF THE NANOFLUIDS VISCOSITY ON TEMPERATURE AND SHEAR RATE

A Brookfield DV-II + Pro rotational viscometer was used to study the viscosity of 7 samples of concentrated nanodispersed systems (nanofluids) with a similar viscosity (6-22 mPa ∙ s), the particles of the dispersed phase in which are nanosized surfactant micelles and conglomerates from them. It was found that for 5 out of 7 studied reagents, there is a decrease in viscosity typical for dispersed systems with an increase in the shear rate, and their flow curves, that is, the dependence of the shear stress on the shear rate, correspond to the ideal plastic flow of non-Newtonian fluids. Moreover, with high reliability, R2 ≥ 0.999 is described by the Bingham equation with a small value of the limiting shear stress (less than 0.2 Pa). It is shown that all the studied reagents are also characterized by an increase in the activation energy of a viscous flow Е with an increase in the shear rate. As a result, a decrease in viscosity with an increase in shear rate, typical for disperse systems, including nanofluids, is provided by a more significant increase in entropy changes ΔS compared to Е. It has been substantiated that, depending on the ratio between the activation energy of viscous flow Е and the change in entropy ΔS, the viscosity of concentrated micellar dispersed systems with an increase in the shear rate can decrease, remain unchanged, and increase. The last two cases, not typical for disperse systems and nanofluids, were identified and studied using the example of two demulsifiers, RIK-1 and RIK-2, with a maximum of a very narrow particle size distribution at 160 ± 5 nm, corresponding to the size of a special type of very stable micelles Surfactant — vesicle.

Meta-analysis of viscosity of aqueous deep eutectic solvents and their components

Deep eutectic solvents (DES) formed by quaternary ammonium salts and hydrogen bond donors are a promising green alternative to organic solvents. Their high viscosity at ambient temperatures can limit biocatalytic applications and therefore requires fine-tuning by adjusting water content and temperature. Here, we performed a meta-analysis of the impact of water content and temperature on the viscosities of four deep eutectic solvents (glyceline, reline, N,N-diethylethanol ammonium chloride-glycerol, N,N-diethylethanol ammonium chloride-ethylene glycol), their components (choline chloride, urea, glycerol, ethylene glycol), methanol, and pure water. We analyzed the viscosity data by an automated workflow, using Arrhenius and Vogel–Fulcher–Tammann–Hesse models. The consistency and completeness of experimental data and metadata was used as an essential criterion of data quality. We found that viscosities were reported for different temperature ranges, half the time without specifying a method of desiccation, and in almost half of the reports without specifying experimental errors. We found that the viscosity of the pure components varied widely, but that all aqueous mixtures (except for reline) have similar excess activation energy of viscous flow {E}^{excess}_{eta}= 3–5 kJ/mol, whereas reline had a negative excess activation energy ({E}^{excess}_{eta}= − 19 kJ/mol). The data and workflows used are accessible at https://doi.org/10.15490/FAIRDOMHUB.1.STUDY.767.1.

Temperature Dependence of Protein Solution Viscosity and Protein-Protein Interactions: Insights into the Origins of High-Viscosity Protein Solutions.

Protein solution viscosity (η) as a function of temperature was measured at a series of protein concentrations under a range of formulation conditions for two monoclonal antibodies (MAbs) and a globular protein (aCgn). Based on theoretical arguments, a strong temperature dependence for protein-protein interactions (PPI) indicates highly anisotropic, short-ranged attractions that could lead to higher solution viscosities. The semi-empirical Ross-Minton model was used to determine the apparent intrinsic viscosity, shape, and "crowding" factors for each protein as a function of temperature and formulation conditions. The apparent intrinsic viscosity was independent of temperature for aCgn, while a slight decrease with increasing temperature was observed for the MAbs. The temperature dependence of solution viscosity was analyzed using the Andrade-Eyring equation to determine the effective activation energy of viscous flow (Ea,η). While Ea,η values were different for each protein, they were independent of formulation conditions for a given protein. PPI were quantified via the osmotic second virial coefficient (B22) and the protein diffusion interaction parameter (kD) as a function of temperature under the same formulation conditions as the viscosity measurements. Net interactions ranged from strongly attractive to repulsive by changing formulation pH and ionic strength for each protein. Overall, larger activation energies for PPI corresponded to larger activation energies for η, and those were predictive of the highest η values at higher protein concentrations.

Influence of TiO2 on the viscosity of the molten slag and the confirmation of the acid–base property on TiO2

ABSTRACT The viscosities of high titanium containing slag with TiO2 ranging from 23 to 43 mass%, Al2O3 9 mass% and CaO/SiO2 ranging from 0.3 to 0.7 were experimentally determined by the rotating cylinder method. Experiments were conducted in the temperature range of 1573–1873 K. The effects of TiO2, basicity, and temperature on viscosity were studied. The experimental results indicated that above the liquidus temperatures, the viscosities decrease with TiO2 and basicity increasing. And increasing on CaO content should be more effective in depolymerizing slag structure and lowering viscosity compared to TiO2 addition. Moreover TiO2 behaved as a weak acid oxide in the experiment slags by XPS analysis. Based on the experimental data of CaO–SiO2–Al2O3–TiO2 quaternary system, the activation energy of viscous flow was calculated between 115 and 141 kJ mol−1 depending on the slag composition.

Influence of rheology and activation energy on the structure of protective coatings formed from CMC suspensions with Al powder

Influence of the temperature and rotation speed of the viscometer spindle on the rheological properties of CMC-based suspensions with aluminum powder is considered. It is shown that suspensions belong to pseudoplastic systems. It is established that, with an increase in the activation energy of viscous flow in CMC-based suspensions, the intensity of intermolecular interactions between polymer macromolecules and oxide shells of Al microparticles increases. Using infrared and scanning microscopy, the structure and morphological features of coatings formed from suspensions are studied. It is revealed that the structure hardening of composite coatings occurs due to hydrogen bonds available for interaction in the OH groups of an aqueous solution of CMC.

Rheological behavior of the CaO-Al2O3-based mold fluxes with different Na2O contents

The CaO-Al2O3-based mold flux is expected during the casting of aluminum containing advanced high strength steels. In this study, the rheological behavior of the CaO-Al2O3-based mold fluxes with different Na2O contents was investigated. The results show that the viscosity in the range of 1423–1573 K reduced sharply when the Na2O content increased from 0 wt % to 10 wt %, but the tendency slowed down with further increasing Na2O from 10 wt % to 15 wt %. The activation energy for viscous flow also decreased from 237.76 ± 4.88 kJ/mol to 180.37 ± 7.10 kJ/mol with increasing Na2O. The structure analyses show that the melt networks were mainly constructed by [SiO4]4--tetrahedral, [AlO4]5-tetrahedral and Si-O-Al structural units. These networks were depolymerized with the addition of Na2O since the charge compensation effect from Na+ was relativity weaker comparing with the network breaking effect from O2−. In addition, the break temperature of the mold fluxes also decreased from 1406 K to 1198 K due to the more precipitation of low melting point Ca2Al2SiO7, rather than MgAl2O4 in the mold flux, during the cooling cycle.