Dynamic Viscosity Research Articles

Nonlinear Seepage Mechanism and Evolution Law of CO2 Enhancing Coalbed Methane Recovery

China’s coal seam permeability is low, and the original coal seam gas extraction is difficult. CO2 displacement of coal seam CH4 technology is an effective gas extraction technology. CO2 is injected into the coal seam under pressure, and competitive adsorption occurs with CH4 in the pores. The gas composition is nonuniformly distributed, and its viscosity μ is the dynamic parameter. As the gas is compressible, the pressure drops, and migration distance does not satisfy a linear relationship. Therefore, the gas transport does not conform to Darcy’s law. The mass transfer process and a multicomponent gas competitive adsorption were investigated theoretically and experimentally. The adsorption characteristics and gas compressibility determine the distribution of the gas components in pores and change the gas dynamic viscosity in different regions. The change in the gas dynamic viscosity in the channel is the direct reason for the nonlinear pressure gradient and gas flow curve. The permeability and gas component affect the degree of nonlinear deviation of the gas flow and pressure gradient curve. This affects the nonlinear deviation degree of the curve by changing the gas dynamic viscosity in the pore channel during displacement. The reasonable displacement pressure is the critical pressure (PO) through experimental and theoretical analysis.

Thermal Analysis of MHD‐Modified Hybrid Nanofluid Flow Inside Convergent/Divergent Channel With Heat Generation/Absorption and Viscous‐Ohmic Dissipation

Enhancing heat transfer efficiency and understanding fluid behavior in complex engineering systems is quite challenging. Here, we examine the rate of heat transfer of magnetohydrodynamic (MHD) flow of a modified hybrid nanofluid between two convergent/divergent (CD) channels, considering viscous dissipation, ohmic heating, along with heat production and absorption. The spherical form of nanoparticle provides a basis for dynamic viscosity and thermal conductivity. The transformed ordinary differential equations (ODEs) are solved numerically. The behavior of various physical parameters particularly channel angel (α), magnetic parameter (M), heat source (Hs), and Eckert number (Ec) are stimulated. It is revealed that the velocity behavior is opposite for magnetic strength while temperature increases as the Ec increases for both CD channels. The tetra hybrid nanofluid improves the rate of heat transfer up to 16.783% as compared to the traditional fluid.

Establishing the parameters of the operation mode of the electric pulse automobile muffler

The purpose of the research in the article is to obtain analytical and experimental results on the purification of internal combustion engine exhaust gases by an electric pulse, allowing us to determine the main parameters of the muffler operation. The set goal was achieved by performing the following methodology. A mathematical model of the motion of a gas particle in a muffler has been developed and investigated, the relationship between the capacity of the engine combustion chamber, the number of revolutions of the crankshaft, the pulse intensity, and the dynamic viscosity of the medium has been established. The condition of the muffler operation is determined through the parameter - the distance between the electrodes. The optimality criterion is justified - the smokiness of the gas before and after purification. A nonlinear experimental plan has been compiled using the methods of similarity theory and dimension analysis. An experimental stand has been developed and results linking the process parameters have been obtained. The results obtained are the basis for the methodology for calculating the design of electric pulse mufflers with optimal smoke ratios.

Late quaternary morpho-stratigraphic record of diapir rise in the Cardona salt extrusion, NE Spain. Halokinetic sequences, raised terraces and uplift rates

Active diapirism has received very limited attention from the geomorphological and Quaternary Science perspective, despite the role played by this ground deformation process in the development of landforms and sedimentary environments, and the important practical implications associated with mobile salt structures (e,g., mining, hydrocarbon production, geostorage). The Cardona salt extrusion (NE Spain) was initiated in late Quaternary times from the post-shortening unroofing of the crest of a salt anticline by the entrenchment of the transverse Cardener River. Detailed mapping, outcrop analysis, geophysical data and trenching indicate that the diapir-flanking deposits show halokinetic complexes comprising two types of morpho-stratigraphic units: (1) an older flap of coarse-grained drapefolded colluvial deposits; and (2) younger lacustrine and fluvial deposits in peripheral depressions confined between the upturned colluvial flaps and the country rock slope. These synkinematic units record an overall relief inversion and correspond to the so-called wedge and hook halokinetic sequences, recording ratios between diapir rise rate and sedimentation rate lower and greater than 1, respectively. The radiocarbon ages obtained from several raised late Holocene strath terraces carved in the salt indicate uplift rates within the range of 36.5–12.1 mm/yr, consistent with geodetic data. The spatial variability of the uplift rates can be related to increasing flow rates towards the axis of the salt wall and potential along-strike variations. The relatively high diapir rise rates observed at Cardona diapir, unaffected by contractional displacement loading (tectonic squeezing), is attributed to the youthful stage of the salt extrusion and the low dynamic viscosity of the Cardona Saline Formation, with a low proportion of impurities and a significant amount of potash salts.

Research on rice starch gel preparation and crosslink network structure-rheological property based on direct-writing 3D printing

Amylopectin and amylose components are natural polymers within rice starch granules, intertwined in specific conditions to form gel polymerized with pore crosslink network, has potential printing properties. In this study, a rice starch gel preparation scheme is proposed for stable properties, and starch granule phase transition mechanism is analyzed based on RVA test during preparation, it can be divided into four-stage, swelling, reacting, homogenizing and self-assembling stages. Gel surface tension and contact angle tested with starch concentration effect, a correlation is developed, reflecting a competition result to gel droplet macro-morphology between the intermolecular cohesion and crosslink network. SEM is used to reveal typical crosslink structures of different starch molecular component proportions, providing objective support for starch gel rheologic property change. Results indicate gel interior crosslink network formed under concentration 12 %, the gel with amylose 4.475 % presents better printing accuracy. Gel shear modulus positively correlated with amylose proportion. Japonica gel under 20 % is of higher viscosity and rapid reassembly ability after interior crosslink network is broken. Max dynamic viscosity is positively correlated with starch concentration. The study aims to provide theoretical and practical support for in-depth analysis of rice starch material application in direct-write 3D printing.

Hydrophobic fouling-resistant electrospun nanofiber membranes from poly(vinylidene fluoride)/polyampholyte blends.

This study reports the fabrication of non-woven fibrous membranes from electrospinning blended solutions of PVDF with polyampholytes in N,N-dimethylformamide and methanol. Polyampholytes are macromolecules that have both positive and negative charged units in different side groups attached to the backbone. In this study, we used a random polyampholyte amphiphilic copolymer (r-PAC) synthesized by co-polymerizing a hydrophobic monomer in addition to the positive and negative charged monomer units, to reduce the fouling propensity of PVDF electrospun membranes while preserving its inherent hydrophobicity. Blends of PVDF/r-PAC were electrospun across the full range of compositions from 0/100 to 100/0. Scanning electron microscopic analysis showed formation of beaded fibers with average fibril diameters from 0.09-0.18 μm. The variation in the fiber diameters is caused by the change in surface charge density, dynamic viscosity of the solution, and the instability of the Taylor cone. Bead formation was observed in the mats electrospun from less viscous solutions. Wide angle X-ray scattering showed that electrospun fibers of PVDF crystallized into the electro-active β and γ crystal phases, whereas polyampholytes were amorphous. Thermogravimetry showed that the PVDF/r-PAC blends have a multi-step thermal degradation mechanism while PVDF homopolymer showed single-step thermal degradation. Sessile drop contact angle measurements confirmed that fibers possess high hydrophobicity and super-oleophilicity. Adsorptive fouling experiments with a fluorescently labeled protein confirmed that the fiber mats obtained from the PVDF/r-PAC blends resist protein adsorption, exhibiting highly enhanced fouling resistance compared to the fibers obtained from homopolymer PVDF.

Analysis of Effect of Hemodynamic Parameters on Two-layered Blood Flow in a Mild Stenosed Artery

Arterial stenosis is the lessening of the arterial wall due to the growth of aberrant tissues that prevent adequate blood flow in the human circulatory system and induces cardiovascular diseases. Mild stenosis, over time, can lead to serious and permanent damage if it remains uncured. Navier-Stokes equation in cylindrical polar coordinates system has been extended by two-layered blood flow along the axial direction with appropriate boundary conditions.A steady flow through a stenosed artery has been investigated extensively using the analytical approach in the case of two-layered blood flow. Mathematical expressions for two-layer hemodynamic parameters such as velocity profile, volumetric flow rate, and effect of stenosis progression on parameters with the variation of core and peripheral layered coefficient of viscosity are derived. Moreover, pressure drop, and shear stress have been calculated analytically in an artery with and without stenosis. Peripheral viscosity has less contribution to varying velocity distribution than the core and is proportional to stenosis size.The volumetric flow rate decreases with an increasing viscosity coefficient. Pressure drop and shear stress attain maximum value in the region stenosis occur maximum height in core layer.The present work could serve as a model in biomedical engineering for the cure of vascular-related diseases and has the potential in designing the devices of this field.

Measurement of the dynamic viscosity of water-based nanofluids containing Al2O3, TiO2, and ZnO using the Artificial Neural Network method

Measurement of the dynamic viscosity of water-based nanofluids containing Al2O3, TiO2, and ZnO using the Artificial Neural Network method

Enhancing Process Stability and Quality Management: A Comprehensive Analysis of Process Capability Indices

Process Capability Indices such as Process Capability Index (Cp) and Corrected Process Capability Index (Cpk), along with Process Performance Index (Pp) and Process Performance Corrected Index (Ppk), are most commonly used tools in quality management within manufacturing processes. They determine whether a process is capable of producing products within established tolerance limits, addressing both short-term and long-term variability. Despite widespread use, the analysis of Process Capability Indices often overlooks special variability within processes, which may lead to misleading interpretations of a process's capability, especially when the determination of tolerance limits is inadequately conducted. This article aims to verify the hypothesis that current analyses of Process Capability Indices fail to consider special variability, which could mislead the interpretation of a process's ability to meet its specifications. Statistical analyses were conducted using the Minitab software, based on dynamic viscosity measurements from the production process of solvent-based paint, to explore the implications of special variability on the interpretation of Process Capability Indices. The study revealed that while Process Capability Indices are useful for identifying quality management opportunities, their effectiveness is limited when special variability is present, often resulting in misinterpretations of a process's true capabilities. The findings highlight the need for methodologies that incorporate considerations of all forms of variability to ensure accurate process capability assessments. This gap in traditional analyses can affect the strategic decision-making in quality management, suggesting a critical area for further research and methodological development. The research confirms the need for a revised approach in analyzing Process Capability Indices, advocating for advanced methods that accurately reflect all forms of variability to improve quality management practices. Future research should focus on developing these methodologies to ensure more reliable and effective use of Process Capability Indices in quality management.

Methods for combating asphalt resin and paraffin deposits in the oil industry

A new inhibitor «NDP-22M» was developed to reduce the pour point of highly paraffinic oils and prevent the formation of asphalt, resin and paraffin deposits. The inhibitor contains a nonionic surfactant, a depressant agent and a solvent. The prepared inhibitor has the ability to reduce the pour point and viscosity of oil, as well as to prevent ARPD. The prepared inhibitor was studied on oil brought from the wells of the oil and gas production department of the production association «Azneft», «Oil Pipeline Administration». In this oil, the amount of paraffin is 10.8%. In the course of research, it was found that the effectiveness of adding 300 g/t of reagent to oil is 75%. Keywords: Precipitation; Depressant; Oil; Pour point; Paraffins; Depressive effect; Dynamic viscosity; Viscosity effect.

Application of analytical models for assessment of crude oil dynamic viscosity at different thermobaric conditions

The article describes author approach to application of approximating model based on experimental evidences. This model allows a user to realize assessment of crude oil dynamic viscosity applying only thermobaric conditions. The authors conduct a case study of suggested approach for the purpose of analysis of dynamic viscosity during oil production in an actual field of the Vankorskaya group. The given example presents real experimental data for viscous oil sample, on the basis of which a two-parameter numerical model of dynamic viscosity as function of gas content at different thermobaric conditions is simulated. The benefit of suggested data display mode is the possibility of its direct incorporation in hydro-dynamic simulation for correct assessment of crude oil dynamic viscosity.

Solubility enhancement of Cefpodoxime acid by aqueous solution of paracetamol through acoustical, polarizable continuum model and antimicrobial activity studies

The pharmacological response of an antibiotic depends on the optimum concentration of homogenous solution of the drug and deviation from this may result in major problems with generic and formulation developments of new chemical entities (NCE’s). Further, the introduction of additional new drugs with greater pharmacokinetic activity is limited because of their poor aqueous solubility. In the present work, an attempt has been made to explore the enhancement of solubility and hence the bioavailability or antimicrobial activity of a pharmaceutically significant drug Cefpodoxime acid (CA), a metabolite of third generation cephalosporin antibiotic cefpodoxime proxetil (CP), by the addition of aqueous paracetamol (PA) solution. Ultrasonic investigation has been carried out on the aqueous solutions of PA containing different concentration of CA at ambient and physiological temperatures and at pressure 101.3 kPa. The measured values of ultrasonic velocity, density and dynamic viscosity and the computed acoustical parameters at 303.15 K, 310.15 K and 313.15 K reveal significant intermolecular interactions between unlike drug molecules. The polarizable continuum model (PCM) study for the two drugs in four different solvents is applied in the calculation of free energy of solution (ΔGsol) which provide valid information regarding the mutual solubility of the two drugs and possible enhancement of bioavailability of CA in presence of PA. Antimicrobial activity of CA in the presence of PA in aqueous medium confirms the improvisation of solubility of CA drug. The data obtained through antimicrobial activity studies support the increased pharmacokinetic activity of CA in the presence of PA in aqueous environment.

Experimental study on the performance enhancement of PV/T by adding graphene oxide in paraffin phase change material emulsions

Traditional water-based PV/T systems have low heat storage density, high PV backsheet temperatures, and low energy utilization in practical applications. In this work, nanoparticles were applied to improve thermal conductivity and simultaneously emulsions were added to enhance energy storage density of the conventional heat transfer media. Furthermore, the synergistic effect of nanocomposite Phase Change Material Emulsions (PCME) as the heat transfer medium on the thermoelectric efficiency of PV/T was studied in a real system. Specifically, the water-based 30 % paraffin emulsions with graphene oxide (GO) concentration of 0.01, 0.02 and 0.03 wt% were prepared by ultrasonic stirring and their thermophysical properties were characterized. The results show that the 30 wt% paraffin emulsion with addition of 0.02 wt% GO has the phase change temperature of 35 °C, latent heat of 42.93 J/g, thermal conductivity of 0.505 W/(m·K) and viscosity coefficient of 0.91. It shows the thermal efficiency of the paraffin/GO emulsion increased by 92.28 %, the electrical efficiency increased by 8.87 %, the comprehensive efficiency increased by 45.75 %, and 15.8 % increase in heat collection for the heat exchange tank in comparison with the water. It is concluded application of PCME would improves the thermoelectric performance of the system than traditional water-based PV/T systems.

Research on modeling the thixotropic properties of cementitious systems using regression methods in machine learning

In this study, the rheological properties of cementitious systems were investigated through modeling studies on structural build-up and breakdown area. The area values were calculated using Herschel Bulkley analysis and hysteresis area method. The properties were examined by varying the composition of the cementitious system (cement fineness, C4AF, C3S, C2S, C3A, equivalent alkali and metakaolin ratio) and changes made in the rheological measurement processes (applied shear rate, maximum shear rate and duration). For this purpose, cement paste mixtures were prepared by substituting metakaolin at four different ratios (3%, 6%, 9%, and 12%) into cements with varying C3A content (2.13, 3.60, 6.82, 9.05%). The modeling study of the obtained results was conducted using three different learning methods: Linear Regression Analysis (LR), AdaBoost, and K Nearest Neighbor (KNN), encompassing machine learning and ensemble learning techniques. It was determined that the most dominant parameter affecting the rheology and thixotropic properties of the mixtures is the metakaolin usage ratio. The pre-shear rate was dominant over the duration and maximum shear rate parameters. Effect of the C3A content on dynamic yield stress and viscosity becomes more pronounced with an increase in the applied shear rate. The KNN method has yielded the best results in all experimental modeling studies. Euclidean distance criterion was used in the KNN method. Although the AdaBoost method obtained results close to the KNN method, the opposite situation was observed depending on the number of data. Logcosh, MAE and RMSE metrics were used to evaluate the experimental results. When the results for 3 different metrics in all modeling studies were examined, the success order of the metrics was found to be Logcosh, MAE and RMSE.

Material Memory Properties

<p class="Abstract" style="text-align: justify;"><span lang="sr-Cyrl-BA">The study demonstrates that the representative volume of standard cylindrical samples of rocks, concrete and asphalt represents a continuum from which samples are extracted or structures will be built. The rheological-dynamical analogy (RDA) is used as evidence, along with standard experimental data from the samples and the velocities of P and S waves obtained through ultrasonic testing. Unlike all previously existing theories of multiphase materials, the RDA theory uniformly describes the solid state and fluid flow within the representative volume. The solid state and fluid flow are functionally connected by rheological parameters. Plastic viscosity coefficients describe (memorize) the matter in fluid flow at the moment of its natural formation or artificial preparation.</span></p>

New accelerated rock creep model considering nonstationary viscosity coefficient

Accelerated creep models are popular research topics in rock mechanics. By analyzing the variation in the viscosity coefficient in the accelerated creep stage and defining the viscoplastic internal variable, a general evolution law for the viscosity coefficient was revealed, and a widely applicable accelerated creep model was proposed. First, the creep test data of 24 rock types were collected and analyzed. Subsequently, the contrast between the strength decrease in the accelerated creep-subsequent failure stage and the post-peak strength decrease in the elastoplastic process was evaluated, and the viscoplastic internal variable in the accelerated creep stage was defined. Subsequently, the evolution function between the normalized viscosity coefficient and the viscoplastic internal variable was established. Based on the test data for different rocks, the predicted curves accurately captured the evolution of the normalized viscosity coefficient with the viscoplastic strain increment and confining pressure in the accelerated creep stage. A new accelerated creep model was constructed by modifying the linear viscoplastic part of the Nishihara model using an established evolution model of the viscosity coefficient. The model demonstrated agreement with the experimental data for different rocks and yielded results close to the monitored tunnel convergence data.

Polysaccharide-Controlled Crystallization of Lactose in Sweetened Condensed Milk

Introduction: One of the main problems when storing sweetened condensed milk is the formation of organoleptically perceptible lactose crystals larger than 10 microns. To prevent this defect, the technology of introducing a fine-crystalline lactose seed has widely proven itself, ensuring the production of a high-quality product. However, this traditional technology is energy-intensive, requires large production areas and metal-intensive equipment in the form of vacuum crystallizers. In this regard, research into alternative approaches that prevent spontaneous crystallization of lactose during the production of sweetened condensed milk remains relevant.Purpose: The purpose of this study is to create a composition of polysaccharides to prevent the formation of organoleptically perceptible lactose crystals in sweetened condensed milkMaterials and Methods: The materials used were commercial samples of skimmed milk powder, sugar, polysaccharides and whey protein hydrolyzate powder. The work used the methods of rotational viscometry, electron microscopy and the method of sorption-capacitance determination of bound waterResults: The paper presents data on the influence of individual polysaccharides, as well as their complexes on the process of crystallization of lactose in concentrated milk systems with sugar on the formation of a stable structure of matrices, reflecting the ability to have both positive and negative effects of hydrocolloids on the process of crystallization of lactose and changes in dynamic viscosity. For multicomponent complex systems containing carboxymethylcellulose, sodium alginate, tara gum, locust bean gum and gum arabic, both a synergistic effect, consisting in the intermolecular interaction of polysaccharides and slowing down the spontaneous crystallization of lactose, and an antagonism effect, manifested in an increase in crystal size, have been establishedConclusion: The composition containing tara gum, carboxymethylcellulose and gum arabic showed the most pronounced properties for inhibiting the growth of lactose crystals, as well as high thixotropic properties. In practical terms, the use of this complex additive for the production of condensed milk products with sugar by the method of restoring dry components can replace the classical process of seeding fine-crystalline lactose, and, accordingly, reduce the energy and metal consumption of the process of crystallization of lactose in the product

Shear viscosity coefficient of magnetized QCD medium with anomalous magnetic moments near chiral phase transition

Shear viscosity coefficient of magnetized QCD medium with anomalous magnetic moments near chiral phase transition

Research of the dispersing and strengthening additives’ influence on the properties of slips and alumina ceramics samples from active alumina

The effect of dispersing and strengthening additives on the rheological properties of aqueous slips made from new brands of alumina produced by a German company was studied. The optimal quantities of dispersing additive for slips from all researched new brands of alumina were determined: for less dispersed alumina — 0.3 % and more dispersed alumina — 0.4 %, the introduction of which reduces the dynamic viscosity of slips to minimum values of — 30 mPa·s, 70 mPa·s and 110 mPa·s, respectively. It has been established that slips made from all researched new brands of alumina with the optimal dispersing additive quantity are characterized by high sedimentation stability and in combination with 0.2 % strengthening additive the sedimentation stability of slips increases.
 The main properties indexes of the samples from new brands of alumina before and after firing at a temperature of 1580 °C were determined. It was established that green samples from new brands of alumina are characterized by apparent density 2.23 g/cm3, 2.19 g/cm3, 2.18 g/cm3 and cold crushing strength 1.1 N/mm2, 1.0 N/mm2, 0.8 N/mm2, respectively, and samples after firing at 1580 °C by apparent density 3.75 g/cm3, 3.90 g/cm3, and 3.86 g/cm3, open porosity 3.3 %, 0.5 %, 0.4 % and bending strength 150 N/mm2, 180 N/mm2, 200 N/mm2, respectively.
 As a result of the performed research, it was established that new brands of more dispersed alumina are suitable for the production by the slip casting method in plaster molds of alumina ceramics with open porosity up to 0.5 % and bending strength ~ 180—200 N/mm2.
 According to the performed research results the technology of alumina ceramics by slip casting in plaster molds method was improved and the raw material base for its production was expanded.

Influence of the impurity content on the density and viscosity of olive oily fluids

In this work, as a case study, the measurement of the density (ρ) and the dynamic viscosity (µ) of 12 different fluids (taken from a conventional oil mill) has been carried out. The variability of the samples processed shows that their impurity contents c (between 0.5-5.87%), together with the temperature t (which varied between 20-30 ºC), can affect the values of ρ and µ. However, this variation has been shown to be different depending on the case, being of the order of 1% for density or even more than 50% for dynamic viscosity. The fact that µ can be sensitive to the presence of impurities opens up a line of study that could be used to estimate such impuritiy content, in real time, by means of relatively simple methods.