ABSTRACT The shortage of freshwater resources has been a big problem faced by hydraulic fracturing, especially since the application of volume fracturing. But at the same time, a large amount of produced water treatment has brought a huge economic burden to the oilfield companies. In this work, a study on the continuous preparation of polymer fracturing fluid with produced water from the thermal recovery of heavy oil was carried out. Based on the analysis of the technical difficulties of continuously preparing polymer fracturing fluid with high-temperature produced water, polyacrylamide modification was carried out to reduce the initial viscosity of the produced water-based polymer solution. To promote the dissolution of the polymer, a solvent was selected. This made the viscosity of the polymer solution reach 80% of the final viscosity within 3 min at a temperature between 40°C and 80°C. The shear viscosity was maintained above 80 mPa·s at 90°C. By screening defoamer, a new defoamer that combined anti-foaming and de-foaming performances was prepared, which can control the foaming capacity of less than 7.5%. The foam can be eliminated within 90 s. This technology has been successfully applied in the Mahu oilfield and relieved the pressure of the freshwater shortage in hydraulic fracturing and produced water treatment.

Abstract Flow assurance issues concerning wax precipitation in crude oil transportation pipelines make it necessary to predict the flow behaviour at different operating conditions. This work attempted to model measured shear stress and viscosity of waxy crude oils using tree‐based machine learning methods and consider wax content, additives, and solvent concentration as input parameters of models. Amongst all implemented techniques, the Extra trees model performed as a potential estimator in waxy oils rheology studies. Two models were run using the final values collected during hyperparameter tuning for shear stress and viscosity. Results show a root mean squared error value of 14.15 and a coefficient of determination ( R 2 ) of 0.998. RMSE of shear stress training dataset was reduced to 9.50 from 35.46 by adjusting hyperparameters of the model. The assessed techniques encompass decision tree, extra trees, gradient boosting, light gradient boosting machine, linear regression, random forest, ridge regression, and XGBoost. Also, in this research, three rheological models of power law, Dekee and Casson models have been used to correlate apparent viscosity values, and it was concluded that Dekee and Casson models have shown an acceptable match with experimental data. Also, the rheological behaviour of three crude oils in the absence/presence of flow improvers was investigated, and it was concluded that ethylene‐vinyl acetate (EVA) copolymer has performance in changing the flow behaviour from non‐Newtonian to Newtonian even at temperatures below WAT. Moreover, the addition of small quantities of asphaltene solvents, such as toluene, can improve the viscosity of crude oil with high wax content.

Glass transition temperature and shear viscosity of pre-copolyethers correlated with their end-groups

Heat-induced evolution of myosin aggregation patterns: The role in regulating interfacial layer lateral-longitudinal interactions.

Shear viscosity for a pure glue theory using an effective matrix model

The performance of the flexible pavement is based on the characterization of hot mix asphalt (HMA). The alterations in climatic conditions and traffic loading influence the rheological properties of asphalt. The asphalt viscosities are an important parameter of asphalt that gives resistance to permanent deformation and stability in the various application areas. Polymer modification can be used to enhance Viscoelastic properties of asphalt binder to enhance its resistance against rutting and cracking. This study developed polymer-modified asphalt samples and tested them using a dynamic shear rheometer at seven temperatures (46, 52, 58, 64, 70, 76, and 82 oC) for frequency sweep (1 to 100 rad/s). Master curves were developed by choosing 64 oC as a reference temperature and applying shift factors. The results depicted that the polymer modification has a substantial influence on enhancing the elastic behavior of asphalt. Attock PMA sample is stiffer compared to laboratory polymer-modified asphalt (PMA) samples, which is determined by the high zero shear viscosity. The behavior of PMA samples at 1.7% and 2.0% of polymer content is similar, which indicates that 1.7% of polymer content can be used as the optimum value for polymer modification. A 2nd-degree polynomial model has the best fit for the master curve of complex viscosity with R2 = 0.921. The values of ZSV indicated that the PMA samples are resistant to permanent deformation, because it increases the stiffness and elasticity of the samples. These findings involve substantial information as to the practical use of polymer-modified asphalt and the way it can be applied in the improvement of pavement performance, durability and offer valuable information on how to select materials to use in designing an asphalt mix.

Introduction: Carbon Fiber (CF)-reinforced thermoplastic composites have been widely used in different structural applications due to their superior thermal and mechanical properties. Nitric acid-modified carbon fiber increases its surface roughness and improves the mechanical properties of the modified composite. Rheological properties have a significant influence on the molding of composite materials. Therefore, it is necessary to test the rheological properties of chopped-carbon-fiberreinforced ABS composites. Materials and Methods: The chopped carbon fiber with 65%-68% concentration of concentrated nitric acid reinforced Acrylonitrile Butadiene Styrene (ABS) composites (CF/ABS) were prepared by an internal mixer and two screw extruder machines in the paper. Results: The results show that when the die diameter was 1.0 mm, the influence on shear viscosity was relatively stable with changes in shear rate and temperature, and the "isothermal aging" method can be used to better visualize and predict the melt shear viscosity. The results of tensile viscosity calculated by the Cogswell method showed that the CF/ABS melt showed a phenomenon of "shear thinning" with increasing tensile strain rate. The tensile viscosity of pure ABS was the lowest, and the tensile viscosity of the composites increased significantly with the increase of CF mass. Discussion: The shear rheological properties and tensile rheological properties of chopped carbon fiber–reinforced ABS composites of different quality were analyzed using capillary die diameters of 0.5 mm, 1.0 mm, and 1.5 mm, respectively. conclusion: With the change of tensile strain rate and temperature, 1.0mm die melt was more likely to flow in tension, which was convenient for composites processing. Conclusion: With changes in tensile strain rate and temperature, the 1.0mm die melt was more likely to flow in tension, which was convenient for composite processing.

An optimized extrusion process is desired for both an environmentally friendly and economically sustainable recycling process. The aim of this study is to simulate the melt conveying zone of a single-screw extruder when using contaminated polymers instead of commonly used pure materials, to optimize a mechanical recycling process, and to reduce the number of measurements needed for rheological input data by using mixing rules. Polypropylene (PP) is blended with a polyamide 12 (PA 12) grade and another PP grade to introduce polymer impurities into the material. The blends are subjected to extrusion experiments in a lab-scale single-screw extruder with pressure and temperature sensors along the barrel. An isothermal analytical simulation model is proposed using representative shear rate values and rheological mixing rules to calculate the pressure distribution along the screw channel throughout the melt conveying zone. The rheological input data for the simulation is taken from high-pressure capillary rheometric measurements, but also substituted with values derived from mixing rules. The results show that the application of the shear viscosity through mixing models yields simulated pressure values similar to those measured in the experiments. With the introduction of representative viscosity into the model, relative deviations of around 5% at certain screw speeds can be achieved.

ABSTRACT Cross‐linked polyethylene (XLPE), widely utilized in electrical cables for example, remains a challenging material to recycle. While thermo‐mechanical devulcanization has been extensively studied for rubber recycling, its application in regenerating XLPE still requires an in‐depth investigation of the correlation between process parameters and ultimate material properties. Here, XLPE waste was regenerated by flash extrusion at high temperatures and shear. A thorough characterization of the so‐obtained polyolefins (rXLPEs), including gel content and chemical analyses such as NMR and SEC afforded a comprehensive picture of the mechanisms involved in the regeneration process—namely chain scission or chain branching—depending on the extrusion temperature. We address viscoelastic properties combining extensional and shear rheology finally establishing distinct relationships between polymer molecular structure and rheological behaviors. Moreover, when rXLPEs are reincorporated into virgin linear polyethylene (20% wt. of rXLPE), the resulting blends acquire unique and individual features. Depending on the regeneration temperature of rXLPEs, the blends exhibit different processability under high shear conditions comparable to industrial continuous processing as well as a wide range of elongational and shear viscosity. This exploration in rXLPE performances offers a novel insight into a regeneration process easily extendable at large scale, paving innovative ways for applications on cable waste.

This study investigates gelatine and sodium alginate as novel thickening agents for pigment textile printing using natural eco-friendly binders. As a thickener and binder, gelatine was tested in different ratios to sodium alginate. The study found that shear rate significantly affected gelatine gel-based thickener shear stress and viscosity. The study examined gelatine-based thickening agents’ elasticity and performance when thinned. The study found that adding sodium alginate increases apparent viscosity compared to gelatine gel alone. A 50:50 gelatine-alginate thickener ratio produces optimal printing paste viscosity. The samples with gelatine and sodium alginate had the highest K/S, while those without gelatine had the lowest. The study tested printed fabrics for light, washing, sweat, and rubbing fastness. All printed fabrics with pigment and gelatine/alginate (1:1) thickener had deeper color depth. After 15 days at ambient temperature, gelatine-based thickening printed fabrics were tested for antibacterial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans.

Precise forecasting of shear stress, viscosity, and density for an aqueous CuO/CaCO3/SiO2 ternary hybrid nanofluid utilizing the artificial neural network

Guar gum (GG) is a classic polysaccharide gel former in drilling fluids, but its native network is hindered by high water-insoluble residue, modest yield-point (YP) build-up and poor tolerance to temperature ≥ 120 °C and salinity ≥ 12 wt% NaCl. Here we transformed GG into a sulfonated guar gum (SGG) hydrogel via alkaline etherification with sodium 3-chloro-2-hydroxy-propane sulfonate. FTIR, EA and TGA corroborate the grafting of –SO3− groups (DS = 0.18), while rheometry shows that a 0.3 wt% SGG aqueous gel exhibits 34% higher YP/PV ratio and stronger shear-thinning than native GG, indicating a denser yet still reversible three-dimensional network. In 4 wt% Ca-bentonite mud the SGG gel film reduces API fluid loss by 12% and maintains YP/PV = 0.33 after hot-rolling at 120 °C, a retention 4.7-fold that of GG; likewise, in 12 wt% NaCl brine the gel still affords YP/PV = 0.44, evidencing electrostatically reinforced hydration layers that resist ionic compression. Linear-swell tests reveal shale inhibition improved by 14%. The introduced –SO3− functions strengthen inter-chain repulsion and water binding, yielding a thermally robust, salt-tolerant polysaccharide gel network. As a green, high-performance gel additive, SGG offers a promising route for next-generation water-based drilling fluids subjected to high temperature and high salinity.

A bstract Recent Bayesian analyses of heavy ion collision data have established a non-trivial temperature dependence of the shear and bulk viscosity per entropy. Motivated by this, we consider higher derivative corrections to realistic, bottom-up holographic models of quark-gluon plasma based on five-dimensional Einstein-dilaton theories and determine the dilaton potentials in the higher derivative terms by matching the Bayesian analyses. A byproduct of our analysis is the bulk viscosity that follows from the holographic V-QCD theory. Higher derivative corrections when treated perturbatively lead to tension with existing data. We investigate possible resolutions.

The risk of environmental accumulation of aluminum ash and red mud is increasing, emphasizing the demand for high-value utilization. In this study, the conversion of aluminum ash and red mud into porous refractory materials with good thermal insulation performance is successfully demonstrated, demonstrating that both residues can be recovered as a resource and their environmental impact can be reduced in a sustainable manner. The phase composition and microstructure of the waste are evaluated by XRD and SEM/EDS, respectively, while their high-temperature behavior and performance were assessed through visual high-temperature furnace testing. The influence of the aluminum ash-red mud ratio on the rheological behavior of slurries containing surfactants at a constant alkaline pH was highlighted. A slurry composition of 40% red mud and 30% aluminum ash exhibited the lowest shear stress and viscosity values, required to facilitate bubble growth. Building on this formulation, foaming with 2% (mass fraction) H2O2 at 80 °C and sintering at 1250 °C produces a material with the optimum performance: a compressive strength of 1.03 MPa, a porosity of 58.55%, and thermal conductivity of 0.19 W/(m·K). The material exhibits long-lasting stability at temperatures ≤ 1100 °C. Thus, complementary compositions of aluminum ash and red mud show potential for practical application and value addition in the preparation of porous refractory materials with thermal insulation properties.

Viscosity reflects the resistance of a fluid to flow and plays a fundamental role in fluid dynamics across several scales. Still, its microscopic mechanisms at the individual particle level remain a subject of ongoing research. Here, we systematically investigate the shear viscosity of two-dimensional (2D) simple fluids using computer simulations of three different systems. We propose a simple formula for the shear viscosity that is solely determined by the lifetime of local atomic connectivity τLC, namely the average time an atom remains bonded with its neighbors, and the average particle velocity. The derived analytical expression shows excellent agreement with the simulation data. We also construct a model for τLC based on the local atomic structure and we show that the microscopic length scale associated to viscosity directly determines the propagation limit of collective shear waves in liquids, linking atomic motion to collective dynamics.

ABSTRACT Plasmakristall‐4 (PK‐4) is a microgravity complex plasma laboratory operated for 10 years on board the International Space Station. Its main purpose is the particle‐resolved investigation of generic condensed matter phenomena using strongly coupled suspensions of microparticles immersed in low‐pressure gas‐discharge plasmas. In PK‐4, both structural (string‐like order) and transport (shear viscosity and heat diffusivity) properties of the microparticle suspensions were investigated. At the same time, the (polarity‐switched) dc discharge in which microparticle suspensions are trapped in PK‐4 exhibits a number of dust‐induced plasma phenomena. In this review article, both types of phenomena as well as connections between them are discussed. The physics encountered in the PK‐4 experiments is therefore reviewed in its entire complexity.

In this article, we study the linear stability of a two-dimensional non-isentropic compressible fluid with vanishing shear viscosity in the context of Couette flow on an infinitely long flat torus \(\mathbb{T} \times \mathbb{R}\). By employing explicit weighted energy estimates and the Fourier multipliers method, we first establish the inviscid damping of the incompressible component of the velocity. Subsequently, we derive an upper bound which is superlinear in time for the compressible part of the fluid. Furthermore, we demonstrate an enhanced dissipation phenomenon for the velocity field under certain quality conditions pertaining to the initial density, initial temperature, and incompressible component of the initial velocity field. For more information and the latex file see https://ejde.math.txstate.edu/Volumes/2025/107/abstr.html

A bstract The experimentally observed temperature-dependent shear and bulk viscosities of the quark-gluon plasma (QGP), along with its apparent violation of the Kovtun-Son-Starinets (KSS) bound η / s = 1/(4 π ), necessitate a holographic description that incorporates higher-derivative corrections. We propose a five-dimensional Einstein-Scalar-Maxwell-Gauss-Bonnet model in which a scalar-Gauss-Bonnet coupling H ( ϕ ) encodes leading curvature corrections. Although no closed-form black hole solution is available, we employ an entropy-production analysis at the event horizon to derive exact analytic formulas for the shear viscosity η and bulk viscosity ζ . These expressions exhibit apparent deviation from the KSS bound and nontrivial temperature dependence. We then perform an independent computation via the retarded Green function (Kubo) method, finding perfect agreement for η and isolating a single constant in ζ that requires numerical determination. Our dual derivation underscores the pivotal role of higher-derivative terms in realistic QGP modeling and demonstrates the efficacy of nonanalytic holographic backgrounds in capturing the dynamics of strongly coupled fluids.

The effect of the high-pressure homogenization (HPH) process (one-stage; applied pressure of 10 MPa and 20 MPa) and furcellaran addition (0.25% and 0.50%, w/w) on the physicochemical and rheological properties of chocolate milk drinks was evaluated. Non-homogenized samples and the milk sample used to produce all model chocolate milk drink samples were also evaluated for comparison. The addition of furcellaran and the HPH process significantly influenced the monitored characteristics of the model samples. In particular, the addition of furcellaran caused an increase in shear stress and viscosity, and HPH also had a noticeable effect on these rheological properties. From the results obtained, it can be concluded that the model samples of chocolate milk drinks exhibited a pseudoplastic behavior. Furthermore, the results of the physicochemical analyses showed a slight increase in dry matter and total soluble solids contents due to furcellaran addition. The solid particle sedimentation values of the tested samples decreased due to furcellaran addition (up to 11.99%.). In addition to the effect on rheological properties, the HPH regime slightly increased the sample's pH values (6.80-6.81). The application of HPH and furcellaran addition may appear advantageous in manufacturing chocolate milk drinks (or dairy-based suspensions) with enhanced physical, flow and sensory properties.

Shear viscosity is the main property linked to the therapeutic effect of thickening products (TP) and can be reduced by the effect of salivary α-amylase during the oral phase and shear thinning during the pharyngeal phase of swallowing. The main aim of this study was to determine the time-effect salivary α-amylase. The study solutions were prepared with three types of TP: modified starch (MS), xanthan gum (XG), and mixture (MX), and two viscosity levels: 250 and 800 mPa·s at 50 s−1. Five volunteers performed oral incubations from 5 to 60 s to assess the time-effect of α-amylase. The results revealed that MS-TP presented a sudden reduction in shear viscosity >99% at 5 s at both viscosity levels. In contrast, XG-TP showed only a slight reduction (1–20%) to α-amylase for all the time intervals. MX-TP viscosity exhibited a reduction of 25% for 250 and 13% for 800 mPa·s. The immediate and extreme reduction in shear viscosity of MS-TP in contact with α-amylase contrasted with the amylase resistance presented by TPs that contained XG. These findings improve the description of the full rheological behavior of TP and provide valuable insights into optimizing the choice of TP in the management of patients suffering from swallowing disorders.