Top Research Papers on Viscosity

The potential for using discarded viscose textiles to produce high-quality viscose fibres is limited by the low molecular weight of the cellulose and its continued reduction in the recycling process. Herein, we present a straightforward approach of reprocessing discarded viscose textiles while achieving high-quality recycled viscose fibres. Discarded viscose textile was defibrated and centrifuged, and the resulting fibres were reprocessed under industrially relevant conditions. The produced viscose dope was fluid and resulted in viscose fibres with properties comparable to fibres made from com...

Elasticity typically refers to a material's ability to store energy, whereas viscosity refers to a material's tendency to dissipate it. In this review, we discuss fluids and solids for which this is not the case. These materials display additional linear response coefficients known as odd viscosity and odd elasticity. We first introduce odd viscosity and odd elasticity from a continuum perspective, with an emphasis on their rich phenomenology, including transverse responses, modified dislocation dynamics, and topological waves. We then provide an overview of systems that display odd viscosity ...

The urgent problem to be solved in heavy oil exploitation is to reduce viscosity and improve fluidity. Emulsification and viscosity reduction technology has been paid more and more attention and its developments applied. This paper studied the viscosity reduction performance of three types of viscosity reducers and obtained good results. The viscosity reduction rate, interfacial tension, and emulsification performance of three types of viscosity reducers including anionic sulfonate, non-ionic (polyether and amine oxide), and amphoteric betaine were compared with Daqing crude oil. The results s...

Metamaterials are composite structures whose properties arise from a mesoscale organization of their constituents. Provided this organization occurs on scales smaller than the characteristic lengths associated with their response, it is often possible to design such materials to have properties that are otherwise impossible to achieve with conventional materials -- including negative indexes of refraction, perfect absorption of electromagnetic radiation, and negative Poisson ratios. Here, we introduce and demonstrate a new material class: viscosity metamaterials. Specifically, we show that we ...

A viscosity sensitive fluorescent probe LBX-1 was devised and synthesized and showed high sensitivity, providing a large Stokes shift as well as an enhancement of fluorescent intensity from methanol solution to glycerol solution, which suggested that the probe could be utilized in monitoring the changes of mitochondrial viscosities in complex biological systems.

Viscosity Viscosity Clear liquid above has lower viscosity than the substance below SI symbol: μ, η SI unit: Pa·s = kg/(s·m) Derivations from other quantities: μ = G·t Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or tensile stress. In everyday terms (and for fluids only), viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity. Put simply, the less viscous the fluid is, the greater its ease of movement (fluidity). [1] Viscosity describes a fluid's in...

Surface rheology becomes important for droplets with adsorbed proteins, solid particulates, lipids, or polymers, and understanding how surface rheology alters basic droplet processes like coalescence provides insight into the processing of dispersions in industrial and biological systems. In this work, we model the approach of two equal-size deformable droplets under an axisymmetric, biaxial extensional flow in the Stokes flow limit. We explore how the viscosity contrast between the drop and suspending fluid alters the film drainage behaviour when interfacial viscosity is present. For a clean ...

A new red Viscosity probe possessing monoexponential fluorescence decay that makes it attractive for lifetime-based viscosity imaging is reported.

Whereas much is known about the complex viscosity of polymeric liquids, far less is understood about the behavior of this material function when macromolecules are confined. By confined, we mean that the gap along the velocity gradient is small enough to reorient the polymers. We examine classical analytical solutions [O. O. Park and G. G. Fuller, “Dynamics of rigid and flexible polymer chains in confined geometries. II. Time-dependent shear flow,” J. Non-Newtonian Fluid Mech. 18, 111–122 (1985)] for a confined rigid dumbbell suspension in small-amplitude oscillatory shear flow. We test these ...

Protein viscosity is one of the major obstacles in preparing highly concentrated protein formulations suitable for subcutaneous (subQ) injection and the Viscosity Reduction Platform helps in reducing excipients for protein formulation.

ABSTRACT The emulsion of Keratin nano ZnO was prepared by extracting the keratin from wool. Cellulose viscose fabric was treated by plasma and immersed in solution and by special chemical method the fabric was finished with keratin/ZnO. The obtained cellulose composite morphology was studied by FESEM. The peaks shown by FTIR proved the presence of functional groups (amide, polypeptide, O-H and C-H). The result has proven the presence and good distribution of keratin and nano zinc oxide. The treated samples showed very low transmission of UV irradiation indicating good UV blocking. Physical pro...

The response of Newtonian liquids to small perturbations is usually considered to be fully described by homogeneous transport coefficients like shear and dilatational viscosity. However, the presence of strong density gradients at the liquid/vapor boundary of fluids hints at the possible existence of an inhomogeneous viscosity. Here, we show that a surface viscosity emerges from the collective dynamics of interfacial layers in molecular simulations of simple liquids. We estimate the surface viscosity to be 8-16 times smaller than that of the bulk fluid at the thermodynamic point considered. Th...

The hemodynamic milieu differs throughout the vascular tree because of varying vascular geometry and blood velocities, and higher blood viscosity is necessary when the cardiac output and peak blood velocity increase as a part of a sympathetic response or anemia, which occurs following significant hemorrhage.

The viscosity of malignant ascites tended to decrease with increasing temperature, which is common for liquids, and albumin levels tended to be higher in the former than in the latter, which is common for liquids.

High viscosity friction reducers (HVFRs) have been used extensively as agents to reduce friction and transport proppants during hydraulic fracturing. Meanwhile, the recycling of produced water has gained traction due to its environmental and economic advantages. Presently, the predominant friction reducers utilized in the fields are categorized as anionic and cationic HVFRs. Anionic HVFRs are frequently injected with fresh water, while cationic HVFRs are typically used in conjunction with high-total dissolved solids (TDS) produced water. It is believed that cationic friction reducers have be...

Ionic liquids (ILs) offer a wide range of promising applications due to their unique and designable properties compared to conventional solvents. Further development and application of ILs require correlating/predicting their pressure-viscosity-temperature behavior. In this review, we firstly introduce methods for calculation of thermodynamic inputs of viscosity models. Next, we introduce theories, theoretical and semi-empirical models coupling various theories with EoSs or activity coefficient models, and empirical and phenomenological models for viscosity of pure ILs and IL-related mixtures....

It is found that spheroidal squirmers generally exhibit dynamics consistent with their spherical analogues, irrespective of the classification of swimmers as pushers, pullers or neutral swimmers, and the slenderness of the spheroids tends to reduce the impact of viscosity gradients on their dynamics.

Stokesian Dynamics is a well-established computational method for simulating dynamics of many particles suspended in a conventional passive fluid medium. Active fluids composed of self-propelling particles with broken time reversal symmetry permit the emergence of a so-called odd viscosity. In this work, we extended the conventional Stokesian Dynamics formalism to incorporate the additional hydrodynamic effects due to odd viscosity, which enables simulating collective behaviors of many particles suspended in an active fluid medium with both even viscosity and odd viscosity.

Atomically thin flat sheets of carbon, called graphene, afford interesting opportunities to study the role of orientation in suspensions. In this work, we use general rigid bead-rod theory to arrive at general expressions from first principles for the complex viscosity of graphene suspensions. General rigid bead-rod theory relies entirely on suspension orientation to explain the elasticity of the liquid. We obtain analytical expressions for the complex viscosity of triangular and hexagonal graphene sheets of arbitrary size. We find good agreement with new complex viscosity measurements.

This article’s goal is to present a viscometer that makes use of a novel viscometry measurement technique. The post will also suggest brand-new vibration viscometers. The development of new viscometers has allowed for the continuous and instantaneous measurement of liquid viscosity. The viscosity can be precisely measured automatically using these viscometers, which are made for industrial application. These viscosity measurement tools can currently be applied to a number of different tasks, including the research of recently developed oil products, the choice of the best flow characteristics ...

The long‐wavelength gravity and topography of Venus are dominated by mantle convective flows, and are hence sensitive to the planet's viscosity structure and mantle density anomalies. By modeling the dynamic gravity and topography signatures and by making use of a Bayesian inference approach, we investigate the viscosity structure of the Venusian mantle by constraining radial viscosity variations. We performed inversions under a wide range of model assumptions that consistently predicted the existence of a thin low‐viscosity zone in the uppermost mantle. The zone is about 235 km thick and has ...

One of the primary motivations for studying biofuels is to meet global energy needs. Biodiesel, as a promising renewable energy source, has the potential to reduce dependence on fossil fuels if implemented effectively. It is derived from chemical reactions (transesterification) in vegetable oils or animal fats, facilitated by a catalyst that accelerates the reaction. Currently, industrial processes employed by biodiesel plants predominantly utilize homogeneous catalysts. However, heterogeneous catalysts are emerging as promising alternatives in biodiesel production, distinguished by their envi...

One of the hallmark properties of fluids is their shear viscosity which is, among other things, responsible for parabolic flow profiles through narrow channels. In recent years, there has been a growing number of observations of said flow profiles in electronic transport measurements in a variety of material systems, most notably in graphene. In this paper, we investigate the shear viscosity of interacting graphene from a theoretical point of view. We study both a phenomenological as well as a microscopic model and find excellent agreement between the two. Our main finding is collective modes ...

Good agreement of the theoretical predictions with both parts of the new bacteriophage Pf1 complex viscosity measurements are found, including the central transport property for the Pf1 reorientation, the dimensionless rotational diffusivity.

Due to the fact that more conventional heavy oil recovery methods (heating, emulsification, dilution, and other methods) have many shortcomings, they cannot meet the demand of heavy oil exploitation. Therefore, there is a need for new recovery methods. In this paper, the surface of nano SiO2 was modified with a silane coupling agent, KH-560, to prepare a nanoviscosity reducer (NRV), which has high-temperature resistance (300 °C), calcium and magnesium resistance (Ca2+ + Mg2+ > 900 mg/L) and high viscosity reduction rate (>99%). FTIR and SEM measurements showed that KH560 has been successfully ...

The mixing rules' current formalism for ionic liquids is analysed in light of established knowledge from the inorganic molten salt community and the scope of application and limitations of these models are discussed.

The development of superior probes is highly desirable and valuable for viscosity measurement. Herein, we designed and reported a series of diphenylbenzofulvene (DPBF)-based organic luminophores according to the molecular regulation strategy. There are two free-rotating phenyl groups attached to the rigid fluorene skeleton in the DPBF, enabling its unique propeller-like noncoplanar chemical structure. Benefiting from this, DPBFs could feature outstanding PL and ECL emissions with intriguing aggregation-induced characteristics. Experimental and theoretical investigations revealed that substitue...

Abstract We investigate drop break-up morphology, occurrence, time and size distribution, through large ensembles of high-fidelity direct-numerical simulations of drops in homogeneous isotropic turbulence, spanning a wide range of parameters in terms of the Weber number $We$, viscosity ratio between the drop and the carrier flow $\mu _r=\mu _d/\mu _l$, where d is the drop diameter, and Reynolds ($Re$) number. For $\mu _r \leq 20$, we find a nearly constant critical $We$, while it increases with $\mu _r$ (and $Re$) when $\mu _r > 20$, and the transition can be described in terms of a drop Reyno...

Viscosity is an extremely important property for ion transport and wettability of electrolytes. Easy access to viscosity values and a deep understanding of this property remain challenging yet critical to evaluating the electrolyte performance and tailoring electrolyte recipes with targeted properties. We proposed a screened overlapping method to efficiently compute the viscosity of lithium battery electrolytes by molecular dynamics simulations. The origin of electrolyte viscosity was further comprehensively probed. The viscosity of solvents exhibits a positive correlation with the binding ene...

Ten minutes of preheating were sufficient to reach a temperature of 60°C, reducing viscosity by at least 84%.

The Lorentz reciprocal theorem-that is used to study various transport phenomena in hydrodynamics-is violated in chiral active fluids that feature odd viscosity with broken time-reversal and parity symmetries. Here, we show that the theorem can be generalized to fluids with odd viscosity by choosing an auxiliary problem with the opposite sign of the odd viscosity. We demonstrate the application of the theorem to two categories of microswimmers. Swimmers with prescribed surface velocity are not affected by odd viscosity, while those with prescribed active forces are. In particular, a torque dip...

In this chapter, I describe bulk viscosity as a general concept, and then focus on bulk viscosity in the dense matter present in compact objects. While this review is focused on bulk viscosity in the conditions present in neutron star mergers, I present a history of bulk viscosity research in dense matter, from its role in damping radial oscillations in neutron stars through its current applications in neutron star mergers. The majority of the chapter consists of calculations of the bulk viscosity from Urca processes in generic neutron-proton-electron ($npe$) matter, and then in dense matter c...

This study investigates the viscosity and liquid-solid transition behavior of biomolecular condensates formed by polyarginine chains (Rx) of varying lengths and citric acid (CA) derivatives. By condensing Rx chains of various lengths with CA derivatives, we showed that the shorter Rx chains attenuate the high aggregation tendency of the longer chains when condensed with CA. A mixture of different Rx lengths exhibited uniform intracondensate distribution, while its mobility largely depended on the ratio of the longer Rx chain. Our findings demonstrate a simple method to modulate condensate prop...

Since the pioneering research by Staudinger on dilute solution viscosity and its relation to the polymer molecular weight, viscosity analysis has become a valuable technique for polymer characterization. The conventional approach is based on the Huggins approximation of the solution-specific viscosity by a quadratic function of concentration, c. We show how to reformulate this approach in a universal form by representing a solution-specific viscosity, ηsp, as a generalized universal function ηsp(c) = α(c/c*) + (1 - α)(c/c*)2 of chain overlap concentration, c*, determined at ηsp = 1, with numer...

The head-on collision of drops is governed by the interfacial tension, viscosity, and inertia of the impacting drops. Earlier studies show that depending on the relative magnitude of these forces, the outcome of a head-on collision of two identical drops of the same liquid is likely to culminate in coalescence or reflexive separation. In this study, the head-on collision of drops of miscible liquids having dissimilar viscosity has been investigated numerically. As the two drop liquids are miscible, it is anticipated that the average viscosity of the two liquids will replicate the transition bo...

Odd viscosity arises in systems with time reversal symmetry breaking, which creates non-dissipative effects. One method to probe changes in viscosity is to examine the dynamics of a single probe particle driven though a medium, a technique known as active rheology. We show that active rheology in a system with odd viscosity and no quenched disorder reveals a variety of novel effects, including a speed up of the probe particle with increasing system density when the background medium creates a velocity boost of the driven particle due to the Magnus effect. In contrast, the probe particle veloci...

The slurries demonstrated shear-thinning behavior, and suspension properties stabilized after a relatively short mixing duration, however, micrographs of the slurries suggested their internal structures did not stabilize after the same mixing time.

Ultrasound and viscosity reducers are commonly used methods to reduce the viscosity of heavy oil. In order to compare the viscosity reduction effects of ultrasound and viscosity reducers and study their mechanism of interaction on heavy oil, molecular dynamics simulation was carried out in this paper. First, a molecular model of heavy oil composed of asphaltene, resin, aromatic hydrocarbon, and saturated hydrocarbon was established in this work. Through molecular dynamics simulation, the different effects of ultrasound and viscosity reducers on the viscosity reduction rate, hydrogen bond numbe...

The introduction of a particle into a preexisting nonuniform viscosity field will generally modify the viscosity field in order to satisfy boundary conditions on the particle surface. Here we discuss the effect of this disturbance viscosity on the dynamics of active particles, as well as characterize the relative importance of the local changes in stress versus the nonlocal flow changes due to nonuniform viscosity.

ABSTRACT The quest to have an effective and efficient heat transfer fluids has been a subject of great research interest for several decades. Nanofluids are preeminent fluids that have garnered increased attention recently due to their enhanced thermal properties. Moreover, viscosity is an essential characteristic of nanofluids and for this reason, many research works have been conducted on this subject over the last few decades. In this work, attempt is made to present the viscosity model of nanofluids. In addition, efforts are put forth to examine the existing empirical, semiempirical, and ...

Since there are not many studies on the application of polymeric surfactants in viscosity reduction emulsification of heavy oil, a series of polyether carboxylic acid–sulfonate polymeric surfactants were synthesized. The viscosity reduction performance and the effect of different chain lengths on the viscosity reduction effect were also investigated. The viscosity reduction, emulsification, wetting, and foaming performance tests showed that the viscosity reduction performance of this series of polymeric surfactants was excellent, with the viscosity reduction rate exceeding 95%, and the viscosi...

Water is a unique and abundant substance in biological and chemical systems. Considering its importance and ubiquity, numerous water models have been developed to reproduce various properties of bulk water in molecular simulations. Therefore, selecting an appropriate water model suitable for the properties of interest is crucial for computational studies of water systems. The four-point Optimal Point Charge (OPC) and three-point OPC (OPC3) water models were developed in 2014 and 2016, respectively. These models reproduce numerous properties of bulk water with high accuracy, such as density, di...

Abstract The notion of inertial balanced viscosity (IBV) solution to rate-independent evolutionary processes is introduced. Such solutions are characterized by an energy balance where a suitable, rate-dependent, dissipation cost is optimized at jump times. The cost is reminiscent of the limit effect of small inertial terms. Therefore, this notion proves to be a suitable one to describe the asymptotic behavior of evolutions of mechanical systems with rate-independent dissipation in the limit of vanishing inertia and viscosity. It is indeed proved, in finite dimension, that these evolutions conv...

There are two kinds of viscosities, viz. the true viscosity and the colloidal viscosity. They can be distinguished by the conductivity measurements. The true viscosity give strong effect on the conductivity but the colloidal viscosity give slight effect on it.

The Phonon Hall Viscosity is the leading term evincing time-reversal symmetry breaking in the low energy description of lattice phonons. It may generate phonon Berry curvature, and can be observed experimentally through the acoustic Faraday effect and thermal Hall transport. We present a systematic procedure to obtain the phonon Hall viscosity induced by phonon-magnon interactions in magnetic insulators under an external magnetic field. We obtain a general symmetry criterion that leads to non-zero Faraday rotation and Hall conductivity, and clarify the interplay between lattice symmetry, spin-...

Abstract The aim of the present study is to investigate the linear and nonlinear wave dynamics of a falling incompressible viscous fluid when the fluid undergoes an effect of odd viscosity. In fact, such an effect arises in classical fluids when the time-reversal symmetry is broken. The motivation to study this dynamics was raised by recent studies (Ganeshan & Abanov, Phys. Rev. Fluids, vol. 2, 2017, p. 094101; Kirkinis & Andreev, J. Fluid Mech., vol. 878, 2019, pp. 169–189) where the odd viscosity coefficient suppresses thermocapillary instability. Here, we explore the linear surface wave and...

Table 2. Neutral eigenvalues with decreasing step-size: m = 1, = 1 and R e = 800. 27 Figure captions Figure 1(a). Basic ow of air over water: velocity prooles with wall blowing and water depth D = 0:5; 1:2; 3; 4. Figure 1(b). Basic ow of air over water: velocity prooles with wall suction and water depth D = 0:5; 1:2; 3; 4.. Figure 2(a). Basic ow of air over water: water depth D and corresponding blow-ing/suction. Figure 2(b). Basic ow of air over water: streamlines with wall blowing. Figure 2(c). Basic ow of air over water: streamlines with wall suction. Figure 3. Neutral curves with equal vis...

The goal of this work is to show that replacing neural networks with simple grid functions, along with two novel geometric priors achieve comparable results to INRs, with instant inference, and improved training times.

The early post-merger phase of a binary neutron-star coalescence is shaped by characteristic rotational velocities as well as violent density oscillations and offers the possibility to constrain the properties of neutron star matter by observing the gravitational wave emission. One possibility to do so is the investigation of gravitational wave damping through the bulk viscosity which originates from violations of weak chemical equilibrium. Motivated by these prospects, we present a comprehensive report about the implementation of the self-consistent and second-order formulation of the equatio...

This publication deals with the estimation of viscosity of liquid metals. It is proposed to discuss the possibility to determine this parameter during aerodynamic levitation experiments performed in ground laboratory. Once in liquid state, metallic sample is submitted to acoustic waves through the levitation gas making it oscillate and deform. A high speed camera records the radial periodic deformation during the relaxation period, meaning when incident waves stop. The evolutions of the sample radius over time are extracted from records and compared with analytical model based on the damped os...