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Xanthan gum is a microbial polysaccharide produced by Xanthomonas and widely used in various industries. To produce xanthan gum, the native Xanthomonas citri- 386 was used in a cheese-whey-based culture medium. The culture conditions were investigated in batch experiments based on the response surface methodology to increase xanthan production and viscosity. Three independent variables in this study included feeding times of acetate, pyruvate, and citrate. The maximum xanthan gum production and viscosity within 120 h by X. citri -386 using Box–Behnken design were 25.7 g/l and 65   500 cP, respectively, with a 151% and 394% increase as compared to the control sample. Overall, the findings of this study recommend the use of X. citri -386 in the cheese-whey-based medium as an economical medium with optimal amounts of acetate, pyruvate, and citrate for commercial production of xanthan gum on an industrial scale. The adjustment of the pyruvate and acetate concentrations optimized xanthan gum production in the environment. [ABSTRACT FROM AUTHOR]

Corn oil as a nanofluid base fluid has the problem of easy oxidation, and the addition of tertiary butyl-hydroquinone is expected to improve the antioxidant property of corn oil. In this paper, a new environmentally friendly nanofluid was prepared by using corn oil as a base fluid, A12O3 as nanoparticles, and tertiary butylhydroquinone as an antioxidant to study its settlement stability and antioxidant properties. The content of oxidation products and viscosity of the nanofluids at different times were investigated from the perspectives of particle size, particle mass fraction, antioxidant type, and antioxidant addition. The results showed that the nanofluids produced without surfactant, 100 mL of corn oil, Al2O3 nanoparticles with a particle size of 20 nm and a particle mass fraction of 1.1083% had the best sedimentation stability. The nanofluid with 0.7% of tertiary butylhydroquinone added had the optimum antioxidant properties. There are two phenolic hydroxyl groups in the molecule of tertiary butylhydroquinone, and each of the two phenolic hydroxyl groups provides one hydrogen ion, which forms stable quinone compounds in corn oil, making the oxidation rate of the corn oil slower. When the content of tertiary butylhydroquinone was added at less than 0.4%, the content of tertiary butylhydroquinone was not enough to effectively retard the oxidation reaction of the oil. When the addition of tertiary butylhydroquinone exceeded 0.7%, the antioxidant property of the nanofluid could only be improved slightly, and the oxidation induction time increased slowly, but on the contrary, the viscosity of the nanofluid would be increased greatly. The nanofluid prepared in this paper has the characteristics of environmental friendly and good antioxidant performance, which can effectively slow down the generation of oxidised substances. This study contributes to the further development of antioxidant research of environmentally friendly nanofluids. [ABSTRACT FROM AUTHOR]

9‐Phenylacridine (9‐PA) is an important acridine‐based medicine that has been proven to possess significant anticancer activity and can be used as a photodynamic therapy (PDT) agent. Meanwhile, the possible twisting of the C−C single bond at the C9 position after photo‐excitation makes it a potential probe responsive to changes in the viscosity of living cells. However, the photophysical properties of 9‐PA is poorly understood. In this study, we utilized femtosecond time‐resolved spectroscopy combined with quantum chemical calculation methods to investigate the excited state dynamics of 9‐PA in solutions with different viscosities. Notably, we demonstrated that the viscosity could strongly influence the deactivation pathway of the initially populated S1 (ππ*) state of 9‐PA. In low‐viscosity solutions, the single bond at the C9 could twist after photo‐excitation, leading to a conformation that shows efficient intersystem crossing. However, such process is suppressed in high‐viscosity solutions, resulting a ~2.5 times higher internal conversion (IC) yield. A full picture of the excited state deactivation mechanism of 9‐PA is proposed. [ABSTRACT FROM AUTHOR]

This paper focuses on investigating the initial-boundary value problem of incompressible heat conducting Navier-Stokes equations with variable coefficients over bounded domains in R 3 , where the viscosity coefficient and heat conduction coefficient are powers of temperature. We obtain the global well-posedness of a strong solution under the assumption that the initial data and the measure of the initial vacuum region are sufficiently small. It is worth mentioning that the initial density is allowed to contain vacuum, and there are no restrictions on the power index of the temperature-dependent viscosity coefficient and heat conductivity coefficient. At the same time, the exponential decay-in-time results are also obtained. [ABSTRACT FROM AUTHOR]

Background: Blood viscosity reflects blood viscosity. It is a measure of the blood's ability to flow through blood vessels. Excessive viscosity is a strong indicator of cardiovascular diseases as it can impede blood flow and/or oxygen supply to body tissues. Objectives: This study was conducted to investigate the effect of viscosity on blood sugar levels. Materials and Methods: Seventy-two random blood samples were collected from healthy individuals without diabetes from qualified medical laboratories in the city of Mosul. The blood samples were divided into three groups based on packed cell volume (PCV) results. The first group had a PCV reading below the normal range. The second group had a PCV reading within the normal range. The third group had a PCV reading above the normal range and included both male and female participants aged between 22 and 60 years. Results: The study results showed that an elevated PCV level in the third group led to a decrease in glucose levels compared to the first and second groups. In males, blood sugar levels in the second group were significantly lower than those in the first group. In females, the second group also showed a significant decrease in glucose levels compared to the first group. Conclusion: Increased viscosity due to proteins affects the function of glucose-carrying proteins and results in lower blood glucose levels. [ABSTRACT FROM AUTHOR]

A comprehensive discussion/analysis of the published viscosity data of ethylene glycol, EG, in the temperature range from 260 (just above the freezing point) to 465 K was recently reported in this journal. It was found that some of the reported data sets significantly deviate from each other, and the largest discrepancies were found at the lower end of the temperature interval examined (Mebelli et al. in Int. J. Thermophys. 42:116, 2021). Hence, in this work, the densities and viscosities of EG were measured in the temperature interval starting in the supercooled region at 248 and extending up to 313 K. Well-established experimental techniques were employed, that is, pycnometry and laminar flow viscometry, the relative precision of which were better than 0.5 and 0.5 %, respectively. The density was found to linearly depend on temperature in the temperature range studied; the cubic expansion coefficient was found to be γ = (5.20 + 3.99 × 10−3 T K− 1) × 10−4 K−1. When our experimental density data were applied to calculate the dynamic viscosity values using the correlation dependence published in the aforementioned review (Mebelli et al. in Int. J. Thermophys. 42:116, 2021), the discrepancy between our experimental data and the calculated values is less than 2 % above the freezing point; however, in the supercooled region, the discrepancy increases up to 4 % at 248 K. When the cooling rate is higher than 10 K min− 1 and the sample mass is less than 5 mg, EG does not freeze; it undergoes glass formation (Tg = − 121 °C) as revealed in our DSC experiments. The Arrhenius plot for viscosity data was found to be nonlinear; from the Angell plot, it was concluded that EG is a moderately fragile liquid with the fragility index = 70. [ABSTRACT FROM AUTHOR]

We present hybrid predictive-correlative engineering correlations for the calculation of the viscosity and thermal conductivity of tetrahydrofuran (THF) in the fluid phase. They incorporate critically evaluated experimental data where available, and predictive methods in regions where there are no data and can be applied over the gas, liquid, and supercritical phases. The viscosity correlation is validated from 195 K to 353 K, and up to 30 MPa pressure, while the thermal conductivity is validated in the temperature range 174 K to 332 K, and up to 110 MPa pressure. Both correlations are designed to be used with a recently published equation of state that extends from the triple point to 550 K, at pressures up to 600 MPa. The estimated uncertainty (at a 95 % confidence level) for the viscosity is 10 % for the low-density gas (up to atmospheric pressure), and 6 % for the liquid at temperatures up to 353 K and pressures up to 30 MPa. For thermal conductivity, the expanded uncertainty is estimated to be 15 % for the low-density gas, and 2 % for the liquid phase from the triple-point temperature to 330 K at pressures up to 15 MPa, rising to 4 % at 110 MPa. Due to the extremely limited data available, these correlations should be considered preliminary until further experimental data become available. [ABSTRACT FROM AUTHOR]

Mucus plugging of the respiratory tract occurs in airway diseases, including asthma, chronic obstructive pulmonary disease, and cystic fibrosis. It can cause blockage of the airways, leading to breathlessness and lung failure. Here, we used a ventilatory setup to demonstrate the effect of BromAc® in dissolving mucus plugs in a novel ex vivo ovine obstructive lung model. Mucus simulant was filled into the trachea of freshly slaughtered ovine lungs and ventilated via an endotracheal tube (ETT) using Continuous Mandatory Ventilation. Predetermined single or repeated doses of Bromelain, Acetylcysteine (Ac), BromAc®, and saline control were administered via an Aerogen® vibrating nebulizer and ventilated for 30 or 60 min. Ventilatory recording of resistance, compliance, and tidal volume was conducted, and rheology pre- and post-treatment were measured. A significant decline in airway resistance (p < 0.0001) compared to the saline control was observed when treated with Bromelain, Ac, and BromAc®, with the latter showing a stronger mucolytic effect than single agents. The decline in resistance was also effective in shorter time points (p < 0.05) at lower doses of the drugs. Changes in compliance, peak pressure, and tidal volume were not observed after administration of the drugs. Rheology measurements revealed that BromAc®TM significantly reduced the viscosity of the mucin at the end of 30 min and 60 min time points (p < 0.001) compared to the saline control. BromAc® showed complete dissolution of the respiratory mucus simulant and improved ventilatory airflow parameters in the ex vivo ovine model. [ABSTRACT FROM AUTHOR]

The dynamic local field correction (LFC) of the classical one component plasma is studied with molecular dynamics simulations and analytical theory. Simulation results are obtained for a wide range of frequencies and wavenumbers in the strongly coupled regime. The dynamic LFC generally differs significantly from both the zero and high-frequency limits. The latter is attained at increasingly lower frequencies as the coupling grows. In the long wavelength limit, the frequency dependence of the LFC is studied in detail. Pronounced structure is observed in the vicinity of the plasma frequency and its first harmonic. The results provide access to the plasmon dispersion and are used to test the accuracy of various theoretical approaches. In the low-frequency limit, the simulation data are compared with the predictions of hydrodynamics, which connects the LFC with thermodynamic and transport coefficients. While a direct comparison is typically hindered by the finite size of the simulations, good agreement is found at strong coupling for a relation that connects the imaginary part of the LFC with the viscosity. [ABSTRACT FROM AUTHOR]

This model consists of a porous spherical body rotating in an incompressible conducting fluid in the existence of a toroidal magnetic field. The toroidal field is generated by an electric dipole along the axis of symmetry. The model is split into two parts—the clear fluid region and the porous sphere. The clear fluid area is driven by the momentum equation and the permeable sphere region is driven by the Brinkman equation. The study is being done for the scenario where the impact of viscous force is much more than inertia force. The expression is found for fluid velocity and stream function by the superposition method. The results depict the impact of rotational parameters and the Darcy number on separation parameter. It is shown that the separation is low for the highly permeable sphere. [ABSTRACT FROM AUTHOR]

Different types of acids are needed in the field to achieve various acidizing goals. Currently, there are no reliable acidizing models for multiphase flows and complex multiphysics coupling. This paper derives mathematical formulas for the oil–water acidizing process of a situ self-diverting acid combined with thermal–chemical–fracture interactions and discusses the influence of two-phase oil–water mixture and fractures on the wormhole morphology produced by self-diverting acid. The results show that the spent acid following the acid–rock reaction forms a high-viscosity sealing zone, causing the injected acid to be redirected. The self-diverting acid forms more numerous and longer branches than a conventional acid during single-phase acidizing. In the case of two-phase acidizing, the high viscosity difference produces distinct effects when using self-diverting acid compared with conventional acid. Specifically, the self-diverting acid extends the breakthrough time and forms a wormhole morphology with longer and more complex branches, whereas the conventional acid accelerates the breakthrough of the rock. As the viscosity difference decreases, the wormhole morphology of the self-diverting acid gradually approaches that of a single-phase acid. Large-aperture fractures completely determine the wormhole morphology, while smaller apertures determine the branch morphology of the wormhole. Fractures have a negative acidizing effect in the case of the self-diverting acid, unlike conventional acid. The proposed model accurately simulates the complex acidizing process of a self-diverting acid. [ABSTRACT FROM AUTHOR]

This paper aims to analyze the leading edge cavitation of a double-suction centrifugal pump, focusing on its periodic evolution process and unsteady characteristics. The calculation of external characteristics and the simulation of the leading edge cavitation in the double-suction centrifugal pump were performed based on the turbulent viscosity correction model. The cavitation was studied under three working conditions (0.5, 0.9, and 1.2 times the design flow rate). The position and structural characteristics of the leading edge cavitation were identified. The instability phenomenon and vortex motion in the impeller passage caused by cavitation were analyzed. The results indicate the inlet flow of the impeller and the pressure distribution on the blade surface are the primary factors influencing the characteristics of the leading edge cavitation. The inlet flow of the impeller determines the position of the leading edge cavitation, while the pressure distribution on the blade surface dictates the specific shape and structure of the cavitation. Throughout the development cycle of cavitation, the position of the flow instability region within the impeller shifts from the off-flow area of the leading edge to the tail of the cavitation region. [ABSTRACT FROM AUTHOR]

While exploring and developing oil and gas, well kick and overflow accidents are inevitable. In such an accident, if the drilling bit is not at the bottom of the well, the drilling tool is blocked, or the reservoir contains toxic gases such as hydrogen sulfide, the traditional technique for well control is no longer suitable, and the bullheading method must be adopted to kill the well. However, during bullheading, the flow patterns of gas and liquid are intricate, making gas velocity hard to predict. To solve these problems, a set of visual simulation experimental device for directional well bullheading was built to find out the effects of wellbore inclination, liquid viscosity, gas and liquid velocities, and bubble size on bubble migration characteristics in gas–liquid countercurrent (gas flowing in opposite direction to the liquid). Prediction models of bubble distribution coefficient and rising velocity considering liquid viscosity, bubble size, and wellbore inclination angle were worked out. The experimental results show that small bubbles are mainly located in the center of the wellbore and large bubbles tend to approach the wellbore wall in gas–liquid countercurrent. Increasing wellbore inclination, viscosity, and the velocity of the liquid flowing against the bubbles results in a gradual decrease in Taylor bubble migration speed, which promotes the bubbles' pressing-back, as inhibiting the upward movement of large bubbles is essential for effective bullheading operations. The prediction models of distribution coefficient and bubble migration velocity have an error of less than 10% and 9. 78%, respectively. [ABSTRACT FROM AUTHOR]

A high-stability gel foam is successfully prepared by forming a gel structure in the liquid film using polymer and crosslinker. The foaming properties, gel characteristics, foam stability, and microstructure of the high-stability gel foam are systematically studied. Although increasing the viscosity of the liquid film reduces the foam volume, it significantly enhances the foam stability. Considering the foaming properties, gel characteristics, and economic benefits, the optimal formulation of the gel foam system is determined to be 0.8% surfactant, 0.3% hydroxypropyl guar gum (HPG), and 0.2% organic titanium crosslinker (ATC). Microstructural analysis revealed that, compared to water-based and polymer foams, gel foam has smaller bubble sizes, lower drainage rates, and slower coarsening rates. This improvement is mainly attributed to the increased viscosity and thickness of the liquid film after gel and the formation of a three-dimensional network structure. Water loss rate experiment shows that the foam stability is stronger when the liquid film has certain viscosity and elasticity to resist external disturbances. However, higher viscosity and film strength do not necessarily result in better foam stability. The final water loss rate of the gel foam after being placed at 100 °C for 10 h is 74.45%, much lower than that of other higher-strength gel foams (greater than 99%). Fracture plugging experiments demonstrated that the plugging rate of gel foam is high (80%), whereas water-based foam achieved only 37.5%. The gel foam can effectively plug fractures and expand the swept volume, showing great potential for improving oil reservoir recovery. [ABSTRACT FROM AUTHOR]

The force and mechanical power required to maintain the simple harmonic motion (SHM) of the upper circular surface squeezing a viscoelastic fluid film is analyzed. The amplitude of the displacement of the upper surface is very small compared to the gap width as a function of time. The smoothness of the upper and lower surfaces is characterized by the slip model with two constant parameters, a slip length and a critical surface shear stress. The nonlinear convection terms in the momentum equation are neglected since the viscous forces dominate the inertial forces. The acceleration and deceleration terms are retained since the upper plate oscillates harmonically and the velocity in the fluid is strictly periodic. An exact solution of the governing equations is found as a function of the Deborah number, the Womersley number, the slip length, and the critical surface shear stress. A circular region without slip condition, bounded by a time-dependent radius, appears when the shear stress of the fluid does not exceed a critical surface shear stress. In addition, an annular region with slip up to the radius of the disk appears when the critical surface shear stress is exceeded. Our results show that viscoelastic and hydrophobic effects together with the Womersley number and a critical surface stress cause changes in the amplitude and phase lag of the waveform of the time-dependent radius and the force acting on the wall surface to maintain the SHM of the upper disk. [ABSTRACT FROM AUTHOR]

Understanding the molecular basis of rheological properties is crucial from both experimental and theoretical perspectives. Slit rheometry is commonly employed to measure the viscosity of fluids. This study utilized molecular dynamics simulations to investigate isothermal contraction flow at the nanoscale. Short linear polyethylene chains were uniformly extruded by a constant-speed piston from a reservoir through an abrupt contraction slit into the surrounding vacuum. Overall, die swelling and die wetting phenomena were observed. Molecular chains were stretched within the slit, while those outside the slit shrunk. Notably, the velocity profile within the slit varied with wall slip at different extrusion velocities. The relationship between the apparent shear viscosity and shear rate exhibited two primary characteristics: the first-Newtonian plateau and the shear thinning slope. Therefore, this molecular simulation method effectively demonstrates the general non-Newtonian behavior of macroscopic polymer fluids. [ABSTRACT FROM AUTHOR]

A series of laboratory experiments was conducted to investigate solid object characteristics and fluid properties on the free fall of cylindrical disks into stagnant non-Newtonian ambient. The viscosity and yield stress of the ambient fluid mixtures were controlled by adjusting the concentration of a polymer. Six different fluid mixtures were prepared to develop a relatively wide range of fluid viscosities and yield stresses to examine the behavior of free-falling disks in accordance with the variations in the disk's geometry, density, and mixture parameters. The effects of disks' parameters, such as disk aspect ratio and relative density, on crown formation, pinch-off characteristics, and splash evolution were studied. Experimental results indicated that increasing the disk's density increased the pinch-off depth while a reduction in aspect ratio increased the pinch-off depth. The sinking time diminished with increasing the aspect ratio of disks, and such observations were independent of the rheological characteristics of the fluid mixture. The same devaluation was also experienced for the height of the crown. As the disk's density reduced, the splash curtain became smoother and the waves' intensity attenuated. The energy losses were found to be correlated with the aspect ratio, density, and fluid viscosity. The augmentation of energy losses was linked with different parameters such as aspect ratio, disk density, and ambient fluid viscosity. [ABSTRACT FROM AUTHOR]

A droplet impacting a liquid pool can result in the pinch-off of a regular bubble. In this study, the cavity deformation and regular bubble pinch-off after droplets impacting a liquid pool were experimentally investigated. The results indicate that the phenomenon of regular bubble pinch-off results from the combined effects of cavity expansion and capillary wave propagation. The inertial force, viscous force, and droplet diameter are all crucial to the cavity evolution and the process of regular bubble pinch-off. The cavity depth increases with the droplet's inertial force but does not change with the droplet's viscous force. As the droplet's inertial force increases, the diameter of the regular bubble first increases and then decreases. The diameter of the regular bubble at We = 165 is almost four times that at We = 193. In addition, the peak size of the regular bubble decreases as the liquid viscosity increases, but increases as the droplet diameter increases. These variations in the regular bubble size are explained using a theoretical analysis. Finally, the effects of the inertial and viscous forces on the thresholds between no-bubble and regular-bubble pinch-off regimes are studied. As the Ohnesorge number increases from 1.37 × 10−2 to 2.03 × 10−2, the upper and lower critical Weber numbers for the occurrence of the regular bubble pinch-off can increase by 30 and 25, respectively. The theoretical boundaries of regular bubble pinch-off agree well with the boundaries observed in the experiments. [ABSTRACT FROM AUTHOR]

We address the question of how viscosity impacts the growth of gravitation waves, such as those on the ocean, when they are driven by wind. There is so far no general rigorous theory for this energy transfer. We extend Miles' approach [J. W. Miles, "On the generation of surface waves by shear flows," J. Fluid Mech. 3, 185–204 (1957)], using the same logarithmic wind profile, to incorporate bulk viscosity and derive modified growth rates. Exploiting the fact that water waves fall into the "weak viscosity" regime, we produce analytical expressions for the growth rate, which we solve using the numerical method proposed by Beji and Nadaoka ["Solution of Rayleigh's instability equation for arbitrary wind profiles," J. Fluid Mech. 500, 65–73 (2004)]. Our results confirm that corrections to the growth rates are significant for wavelengths below a meter, and for weak to modest wind strengths. We show that all wave growth is suppressed, due to viscous effects, below a critical wind strength. We also show that the wave age corresponding to a developed sea is reduced by viscosity. We quantitatively characterize the zones, in terms of wind strength and wavelength, for which the wave growth is suppressed by viscosity. [ABSTRACT FROM AUTHOR]

The viscous and rarefaction effects on centerline shock reflection occurring in an overexpanded axisymmetric microjet have been investigated numerically by means of a fully coupled pressure-based shock capturing scheme. Due to the low free-stream Reynolds number, the Navier–Stokes equations were coupled with slip velocity and temperature jump boundary conditions to account for rarefied gas effects in the Knudsen layer. It has been found that pronounced viscosity levels can cause a transition from a three-shock to a two-shock configuration, which is impermissible by inviscid theory. This is the first observation of such phenomena in the case of over-expanded jets. Analysis of the von Neumann and detachment criteria indicates that the transition from Mach reflection to regular reflection is analogous to the dual-solution domain transition for planar shocks. In addition, prediction of the longitudinal curvature of the incident shock has been conducted from a mathematical standpoint. [ABSTRACT FROM AUTHOR]

The aim of the study was to propose pharmacy-compounded oral gels as a new and alternative dosage form that is attractive to children as having a better masking taste than syrups and reducing the risk of spilling. The application and physical properties of the gels prepared with cellulose derivatives (hydroxyethylcellulose and carmellose sodium) or carbomers were evaluated. The results of the study showed the most suitable consistency, viscosity, and organoleptic properties for gels prepared with carbomer and cellulose derivatives at concentrations of 0.75% and 2.0%, respectively. The microbial stability of the gels was guaranteed by the use of methylparaben and potassium sorbate. VAL (valsartan) and CC (candesartan cilexetil) tablets, often used off-label in children, were pulverized and suspended in the hydrogel bases, resulting in final drug concentrations of 4 mg/g and 1 mg/g, respectively. There was no significant change in viscosity and consistency parameters when the pulverized tablets were added, and only small changes in viscosity and consistency were observed during 35 days of storage, especially in the gels with sodium carmellose and candesartan. On the basis of the drug assay, an expiry date of 25 °C was recommended: 35 days for valsartan and 14 days for candesartan preparations. [ABSTRACT FROM AUTHOR]

The Chepaizi Exploration Area, Junggar Basin (NW China) holds substantial importance for seismic exploration endeavors, yet it poses notable challenges due to the intricate nature of its subsurface and near-surface conditions. To address these challenges, we introduce a novel and comprehensive workflow tailored to evaluate and optimize seismic acquisition geometries while considering the impacts of near-surface viscosity. By integrating geological knowledge, historical seismic data, and subsurface modeling, we conduct simulations employing the visco-acoustic wave equation and reverse-time migration to produce detailed subsurface images. The quality of these images is quantitatively evaluated using a local similarity metric, a pivotal tool for evaluating the accuracy of seismic imaging. The culmination of this workflow results in an automated optimization strategy for acquisition geometries that enhances subsurface exploration. Our proposed methodology underscores the importance of incorporating near-surface viscosity effects in seismic imaging, offering a robust framework for improving the accuracy of subsurface imaging. Herein, we aim to contribute to the advancement of seismic imaging methodologies by providing valuable insights for achieving high-quality seismic exploration outcomes in regions characterized by complex subsurface and near-surface conditions. [ABSTRACT FROM AUTHOR]

Foam-based enhanced oil recovery methods are becoming instrumental in increasing hydrocarbon production from unconventional reservoirs. However, the efficacy of such techniques is significantly affected by reservoir heterogeneity and adverse wettability conditions. This experimental study addresses such challenges by investigating the effect of fracture-matrix permeability contrast on the effectiveness of foam-based enhanced oil recovery in fractured oil-wet porous systems under reservoir conditions. Fractured oilwet Minnesota Northern Cream Buff carbonate core samples were employed and fracture permeability was varied using four different mixtures of proppants with varying mesh sizes. An amphoteric surfactant was used as the foaming agent and the aqueous solution was prepared in a synthetic brine of 200,000 ppm salinity. The results showed that foam reduced gas mobility in fractures, diverting gas to the matrix and mobilizing oil toward fractures. The permeability of the fracture showed a significant impact on foam behavior in oil-wet porous systems. It was noted that as the fracture-matrix permeability contrast decreased to a certain ratio, the apparent viscosity of the foam increased, resulting in the enhancement of fracture-matrix interactions and, therefore, higher oil recovery. However, further reduction in this ratio resulted in a significant decline in foam strength. The optimal fracture-matrix permeability contrast was determined when using 100 wt.% of 100 mesh sand, enabling the creation of small and durable bubbles, which notably restricted gas movement and led to higher oil recovery. The results confirm that foam can be a viable and effective alternative to traditional gas injection methods in fractured carbonates with oil-wet characteristics. [ABSTRACT FROM AUTHOR]

To solve the contradiction between reducing water-insoluble content and maintaining high viscosity in the preparation of modified guar gum for oilfield fracturing fluid, in this work, sodium 3-chloro-2-hydroxypropylsulfonate was used as a modifier to prepare sulfonated guar gum. Orthogonal and single-factor extrapolation experiments were conducted to explore the effects of reaction conditions and the optimal process was determined as follows: reaction temperature of 26 oC, reaction time of 2.0 h, sodium hydroxide as a mass fraction of guar gum of 1.0%, and sodium 3-chloro-2-hydroxypropyl sulfonate dosage as a mass fraction of guar gum of 0.5%. Furtherly, the temperature stability, filtration property, and inhibition of formation clay of the sulfonated products were investigated. The results showed that the apparent viscosity of 0.6% solution of guar gum was increased by 33%, the water-insoluble content was decreased by 0.42%, and the temperature stability, filtration resistance, and clay inhibition were all improved. Especially, the viscosity of cross-linked sulfonated guar gum is 100% higher than that of unmodified guar gum. The structure of sulfonated guar gum was characterized and confirmed by infrared spectrum, DSC, thermogravimetric, and elemental analysis. [ABSTRACT FROM AUTHOR]

This article explores the possibilities for improving the characteristics of water-coal fuel suspensions (WCFS) based on high-ash coals from Uzbekistan. Investigations indicate that the incorporation of stabilizing and plasticizing additives, such as sodium and calcium hydroxides, can result in notable enhancements in both rheological characteristics and calorific value of WCFS. These results are important for optimizing production and increasing the technological suitability of WCFS based on high-ash coals from Uzbekistan, which allows them to be used as highly effective fuels. This investigation is a significant advancement towards the progress and enhancement of fuel blends and can be valuable for engineers and manufacturers who are engaged in the manufacturing process of WCFS. [ABSTRACT FROM AUTHOR]

Potent antioxidants, like 3-hydroxy flavones, attracted considerable attention due to their excited state intramolecular proton transfer (ESIPT)-based fluorescence behaviour. This article is an interesting demonstration of a series of synthetic 3-hydroxy flavone analogues having high antioxidant activity as molecular rotor-like viscosity probes. Among these flavone analogues, 4′-N,N-dimethylamino-3-hydroxy flavone (3) is the most potent one, showing the twisted intramolecular charge transfer (TICT)-dependent fluoroprobing activity toward the blood viscosity changes associated with diabetes and free fatty acids (FFA)-induced nuclear viscosity changes of MIN6 cells. The TICT dynamics of (3), which instigates its viscosity probing activity, was comprehended with the help of DFT-based computational studies. Abnormal cellular viscosity changes are the pathological traits for various diseases, and non-toxic flavone-based viscosity probes can be useful for diagnosing such pathological conditions. [ABSTRACT FROM AUTHOR]

The present study investigated the effect of polyphenol-rich Strobilanthes crispus extract (SCE) fortification at various concentrations on yogurt. Proximate data revealed that the moisture, carbohydrate, and protein content decreased as the SCE concentration increased while fat and ash content remained unaffected. A significant decrease in pH, color (L*, a*, b*), and viscosity was noticed across all SCE-fortified yogurts. With an increasing concentration of SCE, a concomitant increment in the total phenolic content (TPC) and antioxidant activity of yogurts was observed albeit statistically insignificant. A weak, positive correlation was found between TPC and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The starter culture (L. bulgaricus and S. thermophilus) remained viable above log 7 CFU/mL for fortified concentrations. The consumer acceptance of SCE-fortified yogurt and the control was similar. Overall, this study suggested that SCE could serve as a potential functional ingredient in yogurt and fortification of SCE at 20% is deemed optimal. [ABSTRACT FROM AUTHOR]

This study examines the effects of annealing process (temperature 50 °C, moisture content of 80%, for 20 h) on physicochemical characteristics (proximate composition, content of resistant starch (RS) and amylose, degree of starch digestibility, shape and size of starch granules, crystallinity, and starch gelatinization profile) of corn flour and corn starch. Two stages of experiment are as follows: 1) verifying the results of the meta‐analysis of corn starch and flour modification by annealing method and 2) analyzing their physicochemical properties. As a result, annealing significantly improves RS content in both groups, reaching 14.18% in annealed corn flour (AF) (compared to 3.27% in native corn flour (NF)) and 21.87% in annealed corn starch (AS) (compared to 3.82% in native corn starch (NS)). The present work also confirms that the treatment unaltered birefringence properties of all samples. Moreover, pasting properties of corn starch and flour demonstrate remarkable changes. The peak viscosity of AS and NS is higher than AF and NF. In addition, gelatinization seems to occur at similar temperature, but needs extra time for starting gelatinization. XRD analysis reveals A‐type crystalline for all samples, while FTIR analysis evidenced that annealing process alters the regions of amorphous and crystalline. [ABSTRACT FROM AUTHOR]

Understanding the thermal aging kinetics of animal oils is of vital importance in the storage and applications of animal oils. In this work, we use four different techniques, including UV-Vis spectrometry, viscometry, impedance spectroscopy, and acid–base titration, to study the thermal aging kinetics of tallow, chicken oil, lard, and sheep oil in the temperature range from 120 °C to 180 °C. The evolutions of the UV-Vis absorbance, dynamic viscosity, electric impedance, and acid titration are discussed with the defect kinetics. The evolutions of the color centers, defects for dynamic viscosity, and electric dipoles follow second-order, first-order, and zero-order kinetics, respectively. The temperature dependence of rate constants for the evolutions of the UV-Vis absorbance, dynamic viscosity, electric impedance, and acid titration satisfies the Arrhenius equation with the same activation energy for individual animal oils. The activation energies are ~43.1, ~23.8, ~39.1, and ~37.5 kJ/mol for tallow, chicken oil, lard, and sheep oil, respectively. The thermal aging kinetics of the animal oils are attributed to the oxidation of triglycerides. [ABSTRACT FROM AUTHOR]

Understanding the amount of bentonite intrusion into rock cracks is necessary to evaluate the performance of natural barrier materials for geological disposal. In this study, assuming a possible chemical action in geological disposals, bentonite was immersed in various solutions to accelerate the chemical action, and a half-year swelling and intrusion experiment was conducted. The experimental results showed that the swelling pressure and intrusion distance of bentonite in a solution environment differed depending on the solution type and that both were smaller than those in a purified water environment. The swelling pressure of bentonite in the environments of the KOH, NaOH, MgCl2, and NaCl solutions decreased significantly, and it did not significantly enter into the gaps in these systems. This is undesired in situations where gaps such as the cracks of rock must be filled. Furthermore, a numerical analysis model was constructed that can simply represent the complex intrusion behavior of bentonite in cracks considering the balance of three forces acting on bentonite. The analysis results confirmed that under conditions where the external swelling pressure fluctuates over time, the intruding fluid fills the cracks more slowly than under conditions where the external swelling pressure is constant. It was also confirmed that under conditions where the viscosity of the intruding fluid decreases over time, the intruding fluid fills the cracks faster than under conditions where the upper limit viscosity is constant. The numerical results clarified that the governing equation for bentonite intrusion into closed cracks may express the long-term intrusive behavior of bentonite into cracks during geological disposal. [ABSTRACT FROM AUTHOR]

Ceramic slurry is the raw material used in stereolithography, and its performance determines the printing quality. Rheological behavior, one of the most important physical factors in stereolithography, is critical in ceramic printing, significantly affecting the flow, spreading, and printing processes. The rheological behavior of SiO2 slurry used in stereolithography technology is investigated in the current research using different powder diameters and temperatures. The results present the apparent non-Newtonian behavior. The yielding characteristics occur in all cases. For single-powder cases, the viscosity decreases when the powder diameter is increased. When the nano-sized and micro-sized powders are mixed in different proportions, a more significant proportion of micron-sized powders will decrease the viscosity. With an increase in the nano-sized powders, the slurry exhibits the shear thinning behavior; otherwise, the shear thickening behavior is observed. Thus, the prediction model is built based on the use of the pelican optimization algorithm-deep extreme learning machine (POA-DELM), and the model in then compared with the fitted and traditional models to validate the effectiveness of the method. A more accurate viscosity prediction model will contribute to better fluid dynamic simulation in future work. [ABSTRACT FROM AUTHOR]

This study investigated the enhancing effects of the temperature-resistant polymer Poly(ethylene-co-N-methylbutenoyl carboxylate-co-styrenesulfonate-co-pyrrolidone) (hereinafter referred to as Z364) on the performance of cocamidopropyl hydroxy sulfobetaine (CHSB) foam under high-temperature and high-salinity conditions. The potential of this enhanced foam system for mobility control during heavy oil thermal recovery processes was also evaluated. Through a series of experiments, including foam stability tests, surface tension measurements, rheological assessments, and parallel core flooding experiments, we systematically analyzed the interaction between the Z364 polymer and CHSB surfactant on foam performance. The results indicated that the addition of Z364 significantly improved the strength, thermal resistance, and salt tolerance of CHSB foam. Furthermore, the adsorption of CHSB on the polymer chains enhanced the salt resistance of the polymer itself, particularly demonstrating stronger blocking effects in high-permeability cores. The experimental findings showed that Z364 increased the viscosity of the liquid film, slowed down liquid drainage, and reduced gas diffusion, effectively extending the half-life of CHSB foam and improving its stability under high-temperature conditions. Additionally, in parallel core flooding experiments, the polymer-enhanced foam exhibited significant flow diversion effects in both high-permeability and low-permeability cores, effectively directing more fluid into low-permeability channels and improving fluid distribution in heterogeneous reservoirs. Overall, Z364 polymer-enhanced CHSB foam demonstrated superior mobility control during heavy oil thermal recovery, offering new technical insights for improving the development efficiency of high-temperature, high-salinity reservoirs. [ABSTRACT FROM AUTHOR]

Sambiloto leaf (Andrographis paniculata (Burm.f.) Wall. Ex Ness) has the potential to be employed as a photoprotective agent due to its high antioxidant content in the form of quercetin and andrographolide. The nanoemulsion preparations can boost the photoprotective activity of sambiloto leaf extract due to its deepest penetration. This study aims to determine the optimum Tween 80 and PEG-400 concentration in the Sambiloto leaf extract nanoemulsion preparation using the factorial 22 design method through Design Expert 12® on pH response, specific gravity, viscosity, and percent transmittance. The optimum formula was tested for sun protection factor (SPF) and DPPH Radical Scavenging activity (IC50). The amounts of andrographolide and quercetin detected in the sambiloto leaf extract were 3.411% and 3.272%, respectively. The optimum formula for nanoemulsion preparations is at Tween 80 and PEG-400 concentrations of 15% and 25%. The optimum Sambiloto leaf extract nanoemulsion formula had a globule size of 172.433±24.312 nm, a PDI of 0.245±0.060, and a zeta potential of -18.100±0.755 mV. The optimum formula for sambiloto leaf nanoemulsion has an SPF value of 44.427 ± 0.081 and an DPPH Radical Scavenging activity (IC50) of 124.863 ± 4.045 ppm. The cycling test showed no significant difference (p>0.05) on organoleptic parameters, pH, specific gravity, and percent transmittance. Based on the results obtained, the optimum formula of Sambiloto leaf extract nanoemulsion has high potential as a photoprotective agent with good globule characteristics and stability. [ABSTRACT FROM AUTHOR]

In the diffuse interface theory, the motion of two incompressible viscous fluids and the evolution of their interface are described by the well-known model H. The model consists of the Navier–Stokes equations, nonlinearly coupled with a convective Cahn–Hilliard type equation. Here we consider a stochastic version of the model driven by a noise of Lévy type, and where the standard Cahn–Hilliard equation is replaced by its nonlocal version with a singular (e.g., logarithmic) potential. The case of smooth potentials with arbitrary polynomial growth has been already analyzed in [G. Deugoué, A. Ndongmo Ngana and T. Tachim Medjo, Martingale solutions to stochastic nonlocal Cahn–Hilliard–Navier–Stokes equations with multiplicative noise of jump type, Phys. D 398 2019, 23–68]. Taking advantage of this previous result, we investigate this more challenging and physically relevant case. Global existence of a martingale solution is proved with no-slip and no-flux boundary conditions in both 2D and 3D bounded domains. In the two-dimensional case, we prove the uniqueness of weak solutions when the viscosity is constant. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the effect of swimming goggles on swimming hydrodynamics by numerical simulations. An elite swimmer volunteered for this research. The swimmer's head was scanned both without goggles, and while wearing 3 different types of goggles (Nikko, Ankor and Swedish). Numerical simulations were conducted at 2 m/s with the Fluent code. The condition without goggles showed the highest viscous drag (1.65 N), followed by the Ankor (1.64 N), Swedish (1.63 N) and Nikko (1.62 N) goggles, respectively. The highest pressure drag was found in the situation without goggles (11.34 N), followed by the Ankor (10.87 N), Nikko (10.78 N) and Swedish (10.20 N) goggles. The condition without goggles presented the highest total drag (12.99 N), followed by the Ankor (12.52 N), Nikko (12.40 N) and Swedish (11.83 N) goggles. Thus, Swedish goggles yields the best hydrodynamics, followed by the Nikko and Ankor goggles and lastly without goggles. Thus, goggles minimise the swimmer's drag comparing to not wearing any. The design of the goggles may impose varying drag forces and therefore it is advised to use goggles at least in competition. [ABSTRACT FROM AUTHOR]

Nanoparticles provide a promising, cost-effective eco-friendly solution to the challenges posed by heavy-oil reservoirs, significantly enhancing oil recovery rates by reducing viscosity without requiring extensive thermal inputs. In this study, carbon nanospheres (CNSs) and functionalized-CNSs nanofluids were prepared by incorporating surfactants (T80 or BMIMCl). These nanofluids were evaluated for their efficacy in upgrading crude oil, particularly focusing on viscosity-reduction. Rheological tests were conducted across varying shear rates (60–300 s−1) and concentrations (0.02–3 wt.%) to comprehensively assess the impact of these additives on the crude oil's proprieties. The results showed a notable enhancement in crude oil viscosity reduction, with the following order observed: CNS-TiO2 < CNS-TiO2/DMIMCl < CNS-TiO2/T80, yielding reduction rates of 95%, 95.83%, and 97.08%, respectively, at an optimal dosage of 2.75 wt.% and a shear rate of 300 s−1. The surface functionalization of CNS particles and their crystallinity are the main mechanisms driving the reduction in oil viscosity. Moreover, the properties of the crude oil were investigated upon the utilization of CNS-TiO2/T80 nanofluid. It was found that this nanofluid led to a substantial reduction in sulfur content by 78.32% and a significant decrease in the percentage of heavier molecules, ranging from C12 to C35 and up to C36, with 47.76% and 97.98%, respectively. [ABSTRACT FROM AUTHOR]

Summary: Aquasoya (AS) powder arouses great interest as a cost‐effective vegan ingredient. In our study, AS was used to develop vegan ice cream products. Different total solid content (TSC) (31%, 33%, 35%, 37%, and 39% w/w) of ice cream mix was changed by the addition of AS powder. pH, emulsion properties, brix, colour, viscosity, overrun, melting properties, texture profile analysis (TPA), and sensory evaluations were investigated. The pH of each AS (31%, 33%, 35%, 37%, 39%) ice cream mix sample was 5.70–5.81, with no significant variance in AS content. Notably, the 39% AS led to higher Brix and viscosity scores. Moreover, the highest overrun in AS ice cream was observed in the sample containing 39% TSC. In contrast, the 31%, 33%, and 35% samples exhibited lower viscosities. However, the 37% and 39% samples displayed higher viscosities, leading to a longer‐lasting appearance. Regarding sensory evaluation, the 39% sample received the highest ratings for overall taste intensity, colour, smell, bean smell, flavour, taste, astringency, and bitterness. However, it scored the lowest for sweetness, softness, and melting degree. Generally, a higher AS content corresponds to stronger overall characteristics. Additionally, acceptance evaluations showed that panels tended to favour ice cream with lower AS content. All these findings suggest that AS ice cream could be potentially developed using vegan ingredients, offering enhanced nutritional and sensory attributes while serving as an effective emulsifier. [ABSTRACT FROM AUTHOR]

Summary: In this study, the effect of different levels (1%–5%) of whole and defatted Moringa oleifera leaf powder (MOLP) on the nutritional composition, physicochemical properties, protein digestibility and consumer acceptability of sorghum mahewu was investigated. The MOLP was boiled and added to the fermented sorghum mahewu. The results demonstrated that sorghum mahewu enriched with whole and defatted MOLP had higher amounts (P < 0.05) of protein, ash and fibre content compared to the control sample. Moreover, minerals, amino acid contents and protein digestibility of the enriched sorghum mahewu samples were significantly improved compared to the control sample. The pH decreased with an increasing proportion of MOLP ranging from 4.36 to 4.09 (mahewu enriched with whole MOLP) and from 4.36 to 4.17 (mahewu enriched with defatted MOLP). Sorghum mahewu samples enriched with whole and defatted MOLP had higher contents of total titratable acid compared to the control sample, while the total soluble solids and viscosity decreased. In terms of colour profile, the b*, and chroma values of sorghum mahewu increased with an increasing percentage of whole and defatted MOLP while L* and a* values decreased. Regarding overall liking, sorghum mahewu enriched with 1% whole and defatted MOLP did not differ (P > 0.05) from the control sample. Therefore, sorghum mahewu must be enriched with low percentages of MOLP to improve its acceptance among consumers. These findings suggest that incorporating medicinal plants such as boiled MOLP to basic foods produced from sorghum flour could improve their nutritional profile and protein digestibility. [ABSTRACT FROM AUTHOR]

At the early stages of drug development, the amount of drug materials is rather limited. In this case, viscosity measurement is often postponed to the later stages, where grams of proteins can be produced. Therefore, it is necessary to develop a viscometer capable of measuring the viscosity with high accuracy while requiring low sample volume. This study presents a novel viscosity measurement technique based on measuring the resonance frequency and motional resistance of a micropillar-enhanced acoustic wave (μPAW) device. The μPAW was developed by fabricating micropillars on the quartz crystal microbalance substrate in order to achieve ultra-high sensitivity, thanks to a unique coupling between the micropillar and the resonator. The experimental measurements demonstrated a nonlinear relationship between the density and viscosity of the fluid and the response of μPAW. A calibration correlation was developed using the response of μPAW in aqueous glycerol and sucrose solutions. The measurements were then extended using high-concentration BSA solutions as the model of protein solution. The main advantage of the μPAW device in this work over other viscometers is the ability to simultaneously measure solution viscosity and protein adsorption on the surface. This is a huge step forward in the development of sensing systems for the pharmaceutical industry, where real-time sensing of target biological proteins and measuring the viscosity of a solution is required. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the mechanical stresses and strains acting on pharmaceutical glass tubing vials during freezing and thawing of model pharmaceutical formulations. Strain measurements were conducted inside of a laboratory-scale freeze-dryer using a custom wireless sensor. In both sucrose and trehalose formulations at concentrations between 5 % and 20 % w/v, the strain measurements initially increased before peaking in magnitude at temperatures close to the respective glass transition temperatures of the maximally freeze concentrated solutes, Tg'. We attribute this behavior to a shift in the mechanical properties of the frozen system from a purely elastic glass below Tg' to a viscoelastic rubber-like material above Tg'. That is, when the interstitial region becomes mechanically compliant at temperature above Tg'. The outputs were less predictable below 5 % w/v and tended to exhibit two separate peaks in strain output, one near the equilibrium melting temperature of pure ice and the other near Tg'. The peaks merged at concentrations between 4 and 5 % w/v where the largest strain magnitude was observed. The strain on primary packaging has traditionally been applied to evaluate the risk of damage or breakage due to, for example, crystallization of excipients. However, data collected during this study suggest there may be utility in formulation design or as a process analytical technology to minimize potentially destabilizing stresses and strains in the frozen formulation. [ABSTRACT FROM AUTHOR]

We show the existence and the regularity properties of (a class of) weak solutions to the two-dimensional stationary incompressible inhomogeneous Navier–Stokes equations with density-dependent viscosity coefficients, by analyzing a fourth-order nonlinear elliptic equation for the stream function. For some stationary symmetric flows, we reformulate the Navier–Stokes equations as ordinary differential equations and give explicit examples of weak solutions. We present some further (ir-)regularity results in the case of piecewise-constant viscosity coefficients. [ABSTRACT FROM AUTHOR]

Disc warping, and possibly disc breaking, has been observed in protoplanetary discs around both single and multiple stars. Large warps can break the disc, producing multiple observational signatures. In this work, we use comparisons of disc time-scales to derive updated formulae for disc breaking, with better predictions as to when and where a disc is expected to break and how many breaks could occur. Disc breaking is more likely for discs with small inner cavities, cooler temperatures, and steeper power-law profiles, such that thin, polar-aligning discs are more likely to break. We test our analytical formulae using three-dimensional grid-based simulations of protoplanetary discs warped by the gravitational torque of an inner binary. We reproduce the expected warp behaviours in different viscosity regimes and observe disc breaking at locations in agreement with our derived equations. As our simulations only show disc breaking when disc viscosity is low, we also consider a viscous criterion for disc breaking, where rapid alignment to the precession vector can prevent a break by reducing the maximum misalignment between neighbouring rings. We apply these results to the GW Orionis circumtriple disc and find that the precession induced from the central stars can break the disc if it is relatively thin. We expect repeated or multiple disc breaking to occur for discs with sufficiently steep power-law profiles. We simulate a polar-aligning disc around an eccentric binary with steep power-law profiles and observe two separate breaking events at locations in rough agreement with our analytical predictions. [ABSTRACT FROM AUTHOR]

Microchannel geometry is an important factor in determining droplet dynamics in droplet‐based microfluidic systems, much like fluid properties and flow conditions. In this context, two important geometric parameters—the contraction ratio (CII ${C}_{{II}}$) and the width ratio (CI ${C}_{I}$)—that are limited to particular value ranges are taken into consideration for evaluation. These parameters interact with the capillary number (Ca ${Ca}$) and viscosity ratio (λ $\lambda $) to affect different aspects of droplet migration and manipulation, such as trap and squeeze regimes. A theoretical model is proposed, and a three‐dimensional numerical simulation method is used in this work. This model predicts the change from trap to squeeze, which is caused by the interaction of the previously mentioned variables. Interestingly, an inverse correlation exists between the width ratio and the critical capillary number for this transition, which is determined as Ca≥f(λ,CII)/CI ${Ca}\ge f(\lambda ,{C}_{{II}})/{C}_{I}$. Furthermore, the investigation explores the droplet elongation and velocity ratio during their passage through the microchannel. By matching input parameters with microchannel geometry, this information may be useful for the design of microfluidic systems, which would facilitate the careful control and manipulation of droplets. [ABSTRACT FROM AUTHOR]

Seminars in Thrombosis and Hemostasis (STH) celebrates 50 years of publishing in 2024. To celebrate this landmark event, STH is republishing some archival material. This article represents the most highly cited paper ever published in STH. The original abstract follows. Blood is a two-phase suspension of formed elements (i.e., red blood cells [RBCs], white blood cells [WBCs], platelets) suspended in an aqueous solution of organic molecules, proteins, and salts called plasma. The apparent viscosity of blood depends on the existing shear forces (i.e., blood behaves as a non-Newtonian fluid) and is determined by hematocrit, plasma viscosity, RBC aggregation, and the mechanical properties of RBCs. RBCs are highly deformable, and this physical property significantly contributes to aiding blood flow both under bulk flow conditions and in the microcirculation. The tendency of RBCs to undergo reversible aggregation is an important determinant of apparent viscosity because the size of RBC aggregates is inversely proportional to the magnitude of shear forces; the aggregates are dispersed with increasing shear forces, then reform under low-flow or static conditions. RBC aggregation also affects the in vivo fluidity of blood, especially in the low-shear regions of the circulatory system. Blood rheology has been reported to be altered in various physiopathological processes: (1) Alterations of hematocrit significantly contribute to hemorheological variations in diseases and in certain extreme physiological conditions; (2) RBC deformability is sensitive to local and general homeostasis, with RBC deformability affected by alterations of the properties and associations of membrane skeletal proteins, the ratio of RBC membrane surface area to cell volume, cell morphology, and cytoplasmic viscosity. Such alterations may result from genetic disorders or may be induced by such factors as abnormal local tissue metabolism, oxidant stress, and activated leukocytes; and (3) RBC aggregation is mainly determined by plasma protein composition and surface properties of RBCs, with increased plasma concentrations of acute phase reactants in inflammatory disorders a common cause of increased RBC aggregation. In addition, RBC aggregation tendency can be modified by alterations of RBC surface properties because of RBC in vivo aging, oxygen-free radicals, or proteolytic enzymes. Impairment of blood fluidity may significantly affect tissue perfusion and result in functional deteriorations, especially if disease processes also disturb vascular properties. [ABSTRACT FROM AUTHOR]

The present studies reported the experimental data on thermophysical properties such as density and viscosity of aqueous solutions of different amino acids namely l-isoleucine, l-proline, and l-glutamine in 1.5 mol/L KCl solution at different temperatures ranging from 298.15 to 323.15 K. Hence, the aim of this study is to investigate interactions between amino acids and KCl solution at dilute concentrations. For understanding amino acid and KCl solution interactions, we will investigate ion–ion and ion–solvent interactions. It has been observed that the density and viscosity rise with amino acid concentration and decrease with temperature. Using the Jones–Dole equation, the viscosity A and B coefficients have been determined. The viscosity B-coefficient values for all the three amino acids in aqueous electrolyte system are depicted as positive. The positive values of B-coefficient indicate a strong alignment of the solvent molecules with solute molecules. The amino acid l-glutamine acts as a structure breaker solute. This structure breaking effect of l-glutamine on solvent may be attributed to the domination of hydrophilic nature of amide group. l-isoleucine and l-proline act as structure maker in electrolyte system. [ABSTRACT FROM AUTHOR]

The viscosity of the film water near hydrophilic surfaces is observed to be significantly higher than that of bulk water, i.e., up to approximately three times that of bulk water. Such an enhancement in viscosity can be attributed to the intensive solid-water interactions, which result in a spatially varying activation energy. An attempt is made herein to investigate the impact of spatially varying viscosity on film flow at the nanoscale. The spatially varying viscosity is described via a proposed viscosity profile equation. A governing equation for film flow incorporating spatially varying viscosity is then established by substituting the proposed viscosity profile equation into the mechanical equilibrium equation. Closed-form solutions for this governing equation are derived by introducing the no-slip boundary condition. The accuracy of the proposed viscosity profile equation and closed-form solutions is evaluated by comparing with experimental and molecular simulation data on viscosity, flow velocity profile, and average flow velocity. The results indicate that overlooking the spatial variation of viscosity can lead to overestimation of flow velocity and hydraulic conductivity for film flow in nanoscale pores by up to 5.5 and 14.0 times, respectively. [ABSTRACT FROM AUTHOR]

We introduce the notion of a nonlinear smooth space generalizing both \operatorname {CAT}(0) spaces as well as smooth Banach spaces. We show that this notion allows for a unified treatment of several results in functional analysis. Namely, we substantiate the usefulness of this setting by establishing a nonlinear generalization of an important result due to Reich in Banach spaces. On par with the linear context, this nonlinear version entails a convergence proof of several other methods. Here, we establish the convergence of a general form of the Halpern-type schema for resolvent-like families of functions. We furthermore prove the convergence of the viscosity generalization of Halpern's iteration (even for families of maps) generalizing a result due to Chang. This work is set in the context of the 'proof mining' program, and the results are complemented with quantitative information like rates of convergence and of metastability (in the sense of T. Tao). [ABSTRACT FROM AUTHOR]

Asphalt aging is a natural process that causes changes in the properties of asphalt, particularly in asphalt adhesion. Previous studies show that the effect of aging on asphalt adhesion performance is not uniform and depends on the asphalt source and aging conditions. To investigate the effects of different SARA (saturates, aromatics, resins, and asphaltenes) ratios and structural changes on the adhesive properties of asphalt after aging, this study employs molecular dynamics simulation to calculate asphalt properties such as density, viscosity, and work of adhesion. The above properties were computed for 12 categories of asphalt molecules, individual SARA components, and asphalt models characterised by diverse SARA ratios, followed by a correlation analysis. The study reveals that asphalt aging increases density, viscosity, and adhesion to silica. The increase in polar functional groups, namely ketone and sulfoxide, is responsible for the enhanced adhesion of asphalt to silica due to the resulting increase in electrostatic potential energy. Different SARA ratios lead to different asphalt properties, with the RA/SA index ((asphaltene%+resin%)/(saturate% + aromatic%)) showing a better correlation with the properties. Positive correlations were observed among density, viscosity, and work of adhesion. This study advances our understanding of chemical and structural effects on aged asphalt properties. [ABSTRACT FROM AUTHOR]

To explore and validate the clinical value of ultrasound (US) viscosity imaging in differentiating breast lesions by combining with BI-RADS, and then comparing the diagnostic performances with BI-RADS alone. This multicenter, prospective study enrolled participants with breast lesions from June 2021 to November 2022. A development cohort (DC) and validation cohort (VC) were established. Using histological results as reference standard, the viscosity-related parameter with the highest area under the receiver operating curve (AUC) was selected as the optimal one. Then the original BI-RADS would upgrade or not based on the value of this parameter. Finally, the results were validated in the VC and total cohorts. In the DC, VC and total cohorts, all breast lesions were divided into the large lesion, small lesion and overall groups respectively. A total of 639 participants (mean age, 46 years ± 14) with 639 breast lesions (372 benign and 267 malignant lesions) were finally enrolled in this study including 392 participants in the DC and 247 in the VC. In the DC, the optimal viscosity-related parameter in differentiating breast lesions was calculated to be A′-S2-Vmax, with the AUC of 0.88 (95% CI: 0.84, 0.91). Using > 9.97 Pa.s as the cutoff value, the BI-RADS was then modified. The AUC of modified BI-RADS significantly increased from 0.85 (95% CI: 0.81, 0.88) to 0.91 (95% CI: 0.87, 0.93), 0.85 (95% CI: 0.80, 0.89) to 0.90 (95% CI: 0.85, 0.93) and 0.85 (95% CI: 0.82, 0.87) to 0.90 (95% CI: 0.88, 0.92) in the DC, VC and total cohorts respectively (P <.05 for all). The quantitative viscous parameters evaluated by US viscosity imaging contribute to breast cancer diagnosis when combined with BI-RADS. [ABSTRACT FROM AUTHOR]

The cure kinetics of 4‐ (dimethylsilyl) butyl ferrocene grafted hydroxyl terminated polybutadiene (HTPB) with Isophorone diisocyante (IPDI) was investigated using differential scanning calorimeter (DSC). Furthermore, the catalytic effect of Iron (III) acetylacetonate (Fe(AA)3) and Dibutyltin dilaurate (DBTDL) on the curing reaction was studied. The experimental data was fitted to Kissinger and Ozawa models, and the kinetic parameters were expressed as Arrhenius activation energy (E), pre‐exponential factor (A) and rate constants. The Crane model was explored to determine the reaction order of the curing reaction. The study categorically showed that the activation energy of the curing reaction with 4‐ (dimethylsilyl) butyl ferrocene grafted HTPB is higher as compared to the pure hydroxyl terminated polybutadiene (HTPB) based system. However, the rate of curing reaction is higher with 4‐ (dimethylsilyl) butyl ferrocene grafted HTPB as compared to HTPB, and the viscosity build‐up data is too aligned with the DSC kinetic study. In addition, both catalysts increased the rate of the curing reaction but Fe(AA)3 displayed a superior catalytic effect. [ABSTRACT FROM AUTHOR]