Higher Dynamic Viscosity Research Articles

NADES systems comprising choline chloride and polyphenols: Physicochemical characterization, antioxidant and antimicrobial activities

Natural Deep Eutectic Solvents (NADES) represent a new group of green and environmentally friendly solvents that comply with all the principles of green chemistry. NADES are formed via hydrogen bonding by combining hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA). In this paper, we presented ten NADES systems based on choline chloride and different polyphenols. The basic physicochemical and biological properties were evaluated (stability, density, viscosity, FTIR, ORAC, antibacterial activity). It was shown that all the systems had a high densities and high dynamic viscosities. The densities ranged from 1.096 – 1.221 mg/mL for ChCl – resveratrol and ChCl – rutin, respectfully. The dynamic viscosities ranged from 0.247–1.662 Pa S for ChCl – gallic acid and ChCl – chlorogenic acid, respectfully. The viscosity could be lowered by increasing the molar ratio of choline chloride. Four NADES systems, comprising catechin, rosmarinic acid, gallic acid and chlorogenic acid could be diluted with water without affecting the stability of those systems. This finding could increase the usability of those systems. The FT-IR analysis of the selected systems showed that the peaks are widened and slightly shifted, without formation of new peaks, which proves the formation of hydrogen bonds between the NADES constituents. All tested systems showed high ORAC value (426.94–874.96 Trolox eq/mL) and antibacterial activity (0.625–2.5 % NADES).

A mass transfer-based LES modelling methodology for analyzing the movement of submarine sediment flows with extensive shear behavior

This study employs the large-eddy simulation (LES) method to investigate the interaction of submarine sediment flows with extensive shear behavior and ambient water. This method is validated with good accuracy by simulating the head velocity and evolution geometries of a submarine mud flow with non-Newtonian fluid characteristics and a submarine turbidity current with Newtonian fluid characteristics in inclined and regular lock-exchange flume experiments. This study finds that the violent mass transfer at the interface of the submarine sediment flow and seawater is caused by numerous eddies, which significantly alter the submarine sediment flow's geometry, resulting in varying degrees of undulation, including the deposition pattern of the submarine sediment flow tail. The acceleration zone, where the velocity of the submarine sediment flow increases significantly at this undulation, propels the sediment flow forward, supporting its long-distance transport. Furthermore, the turbulence and mass transport characteristics of submarine turbidity currents with low dynamic viscosity Newtonian fluid characteristics are stronger than those of submarine mud flows with high dynamic viscosity non-Newtonian fluid characteristics. Therefore, when submarine landslides develop into later stages, such as submarine turbidity currents with high velocity, large volume, and long run-out distance characteristics, more attention must be given to the mass transport process.

Understanding the dynamic rheological property of cement paste blended with steel slag powder: From interparticle force and physico-chemical parameters of view

The blending of steel slag powder with cement can mitigate the carbon footprint of cementitious composites. The rheological properties of cement pastes are well known to be related to interparticle forces. However, the magnitude of the interparticle force depends on many physico-chemical factors. The influence of various factors on interparticle forces is not yet clear, making it difficult to control the rheological properties. In this paper, the interparticle force of steel slag powder blended cement paste was quantified and its relationships with dynamic rheological properties and basic physico-chemical parameters were explored. By means of this, the interparticle force was confirmed to could explain the effect of steel slag powder on the dynamic rheological properties of cement paste within 1 h. Moreover, how physico-chemical parameters affect the interparticle forces was clarified. A cement paste with large particle size and apolar surface energy, as well as small potential square, Debye length and small polar surface energy, can exhibit large interparticle force and high dynamic yield stress and plastic viscosity. A simple formula calculating interparticle force from basic parameters was proposed, which is believed to effectively and practically regulate the interparticle force. The relationships between interparticle forces, physico-chemical parameters, and rheological properties provide an effective reference for regulating the dynamic rheological properties of cement paste through fundamental parameters.

Optical sensitivity of mono and hybrid nanomaterials dispersed PEG-based semiconducting nanofluids with high viscosity and dielectric permittivity

ABSTRACT Semiconducting nanofluids (SNFs), based on poly(ethylene glycol) (PEG200) fluid with the dispersion of 0.01 wt% mono (ZnO, TiO2, and OMMT) and 0.01+ 0.01 wt% hybrid (ZnO+OMMT, ZnO+TiO2, and TiO2+OMMT) nanomaterials, are prepared through mixing and then ultrasonic cavitation homogenised process. Ultraviolet-visible (UV-Vis) absorbance spectra of these SNFs are recorded in the 200–800 nm range and analysed for their photosensitivity and UV shielding performance and also for nanomaterials tunable dual band gaps ranging from 3 to 5 eV. The rheological investigations on these samples, at 303.15 K, validate Newtonian nanofluids of high dynamic viscosity (η ≈ 32 mP.s). Static dielectric permittivity (εs ≈ 22) and electrical conductivity (σdc ≈ 8 μS/cm) of these SNFs at 303.15 K are found marginally affected by the dispersed mono and hybrid nanomaterials. Comparative experimental results presented here in on a variety of SNFs provide a guideline for their uses in developing soft condensed matter based innovative devices.

Biosynthesis of amidated pectins with ultra-high viscosity and low gelation restriction through ultra-low temperature enzymatic method

In traditional industry, amidated pectin was usually prepared by adding ammonia gas under the alkaline condition or ethanol system which degrades the galacturonic acid chain of pectin and weakens the advantage of amidated pectin in gel. In this study, amidated pectin with ultra-high viscosity and low gelation restriction were prepared by grafting with the neutral aliphatic amino acids through enzymatic method at ultra-low temperature to extend the application of the pectin in food, daily use chemical, medicine and other fields. The amino acid grafting ratio of alanine amidated pectin (V-PE), valine amidated pectin (A-PE) and leucine amidated pectin (L-PE) were 14.12%, 24.36% and 18.94%, respectively. The results of dynamic viscosity showed that the dynamic viscosity of high methoxy pectin (HMP) increased from 186 to 39799 (V-PE), 20396 (A-PE) and 23781 mPa.s (L-PE), respectively. Through ultra-low temperature enzymatic, the V-PE with the highest amino acid grafting ratio had the highest solution viscosity and gel hardness. Furthermore, the hydrogel has better thermal stability, which can maintain the three-dimensional network structure of the gel at higher temperatures without collapse. Amidated pectin with ultra-high viscosity and low gelation restriction can provide valuable information in applications such as food and medicine. • Pectin was amidated by neutral aliphatic amino acids through enzymatic method. • In the two-phase system, the amide synthase activity of papain was dominant. • The amidated pectin can form hydrogels under low gelation restriction. • Compared with high methoxy pectin, amidated pectin has high dynamic viscosity.

Напрямки оптимізації розвідки і розроблення нафтових родовищ Західного Причорномор’я України

The southern part of the Dobrogea Foredeep is located in the southwestern regions of Ukraine within the Odesa region. Here, on the territory of the uplifted Bilolissya block, the East Sarata, Zhovtyjar, Saryjar, Zarichna oil accumulations are located in the chemogenic-carbonate layer of the Middle and Upper Devonian. The deposits are confined to limestones and dolomites with secondary fractured-cavernous-porous reservoirs. They lie at depths of 2500–3200 m. During the test of two dozen wells, the filtrate of the drilling fluid with a small amount of oil was received with the estimated flow rates of several tons per day. The rise of the oil level in the wells was quickly stopped, the hydrodynamic connection of the wells with the productive formations was lost. The use of today's known methods of intensification of the flow of hydrocarbon fluids did not lead to positive results. According to the research of microphotographs of reservoir rocks, it is proved that the largest voids of reservoir rocks are filled with immobile bitumen, while the smaller cavities contain mobile oil. Immobile bitumen fills main channels and blocks communication between rock cavities. This is the main reason for the absence of industrial inflows of oil to the wells. Another important reason is the low filtering properties of the collectors. Most of them have a permeability of less than 0.01∙μD. Other reasons for the failure of the industrial development of oil deposits are the high dynamic viscosity of oil due to the high content of asphaltenes, silicagel resins, paraffins, the low energy potential of oil deposits due to their degassing during the long geological time, as well as the lack of hydrodynamic connection of oil deposits with natural water pressure systems. We assume that the Middle and Upper Devonian oil fields of the Western Fore-Black Sea area are most likely mainly bituminous. Given the significant depths of the deposits, their industrial development is technically impossible today. Therefore, it is impractical to plan further scientific research on the mentioned complex. Instead, research should be reoriented to the Silurian terrigenous-carbonate complex and the Lower Devonian terrigenous complex, which are hydrodynamically more closed and in which non-degassed hydrocarbon accumulations can be preserved.

Comparison and analysis of the performance of a spiral groove mechanical seal subjected to phase change with different sealing media

The goal of this research is to investigate the impact of four kinds of easily vaporized sealing media(liquid hydrogen, liquid oxygen, liquid nitrogen and water) on phase change and sealing characteristics of a spiral groove mechanical seal(SGMS). Based on homogeneous flow assumption, a dynamic continuous boiling model is developed taking into account phase change of fluid film. With fluid pressure and fluid enthalpy as primitive variables, the properties of single-phase fluid and mixture fluid can be obtained by REFPROP software. The influence of the sealing medium on phase state stability criterion, steady-state and dynamic performances, and geometric structure parameter optimization is investigated. The findings reveal that dynamic viscosity is the key physical parameter of the sealing medium, affecting the seal stability and the phenomenon of phase change of an SGMS. The sealing medium with a high dynamic viscosity may obviously block the phenomenon of vaporization, which is advantageous in delaying the process of phase change and shortening the temperature range of quasi-vapor phase state in which an SGMS is unstable. The trends of steady-state and dynamic performances of an SGMS undergoing phase transition are identical for any type of easily vaporized fluid indicated in this work as a sealing medium. Taking into account both steady-state and dynamic performances, and independent of the type of sealing medium used, the best range of groove-to-dam ratio of an SGMS undergoing phase change is 0.5 < γ < 1.5.

Numerical simulations of air-assisted primary atomization at different air-to-liquid injection angles

Numerical simulations have been performed for a coaxial, twin-fluid nozzle to study the influence of the angle α between the central liquid jet and the annular airflow on the primary atomization process. A glycerol/water mixture with a high dynamic viscosity of 200 mPas is used and the gas-to-liquid ratio is 0.6. The simulations show good agreement with experiments for the breakup morphology. The liquid jet breaks up quickly and its core length LC decreases with α from 0° to 30°, which is attributable to a reinforced aerodynamic interaction. The flow velocity of the gas phase close to the liquid jet increases with α in this case, which is confirmed by corresponding PIV measurements. This is due to the formation of a high pressure zone at the base of the liquid jet, which results in a favorable pressure gradient in the bulk flow direction. However, further increase of α from 30° to 60° leads to a decreased gas flow velocity along the liquid jet and an increase of LC. The same behavior has been found for the integral specific kinetic energy kL in the liquid phase, which represents a measure for the momentum transfer between the gas and liquid phases. kL increases from α=0∘ to 30° and it decreases again with higher α. Moreover, kL yields a similar distribution compared with the turbulent kinetic energy (TKE) of a typical turbulent flow in the spectral domain. This is attributed to the local concentration of TKE of the liquid phase in a small region around the tip of the liquid jet. The results reveal that, in addition to the common dimensionless operating parameters, the flow direction has an essential impact on the atomization process. According to the current work, the best atomization performance is achieved at an angle of α=30∘. The spectral correlation of kL with TKE of the gas flow may be used to assess the dynamics of the liquid phase.

Assessment of Spray Drift with Various Adjuvants in a Wind Tunnel

When pesticides are sprayed, a significant portion of the droplets drifts away from the target. Using an adjuvant in spray liquid is an easy option for reducing droplet drift because there is no need to make any changes to the sprayer. The objective of the study was to determine the effects of seven commercially available adjuvants (Surfeco plus, Starguar, Kantor, Sterling, Control, Control WM, and Control DUO) with varying active ingredients on droplet size, surface tension, and viscosity. Since these properties affect droplet formation, these adjuvants were evaluated in terms of their drift-reducing performance in a wind tunnel at various wind speeds (2.0, 3.5, and 5.0 m/s) and spray pressures (3, 4, and 5 bars). The ground and airborne components of drift were evaluated. With the use of a patternator, the potential for the ground drift of adjuvants was measured; for airborne drift, polyethylene lines that were stretched along the cross-section area of the wind tunnel at various heights were employed. The number of deposits of a tracer dye–adjuvant mixture that was sprayed on the polyethylene lines was measured via fluorometric methods for determining the airborne drift potential. The test results showed that the adjuvant Control Duo containing a polymer blend, which had the highest dynamic viscosity (4.27 mPa.s), increased the Dv0.5 droplet diameter up to 192 μm at 3 bar with nozzle XR11002. This adjuvant reduced the ground drift potential (Dc) by 60.53% compared to tap water. The maximum airborne drift potential reduction percentage (DPRP) was obtained as 85.76% with Surfeco plus containing organic silicone at a pressure of 3 bar and a wind velocity of 5 m/s. When considering the airborne drift-reduction potential of the adjuvants used, it was found that the adjuvants Control WM, Control, Starguar, and Surfeco plus significantly reduced the airborne droplet drift compared to spraying tap water.

Preparation of Waste-LDPE/SBS Composite High-Viscosity Modifier and Its Effect on the Rheological Properties and Microstructure of Asphalt.

To reduce the cost of high-viscosity modifier (HVM) and alleviate white pollution problems, we prepared the environment-friendly HVM (E-HVM) by using waste-low density polyethylene/styrene-butadiene-styrene (waste-LDPE/SBS) composite. The physical characteristics of the E-HVM modifier were first investigated. Additionally, the effects of E-HVM modifier dosage (8 wt% to 20 wt%) on the rheological properties and microstructure of asphalt were, respectively, researched by dynamic shear rheometer (DSR), bending beam rheometer (BBR), and fluorescence microscopy (FM). The results show that the E-HVM modifier has lower molecular weight, and its distribution is wider than that of the Tafpack-Super (TPS) modifier; thus, the E-HVM modifier had better compatibility with asphalt, which has also been proven by FM images. Due to these reasons, the E-HVM modifier improves the high-temperature performances of asphalt more effectively than the TPS modifier, which is shown by the higher dynamic viscosity (60 °C) and G* and the lower and Furthermore, compared to TPS modified asphalt, E-HVM modified asphalt also has a higher fatigue life at different strain levels (2.5% and 5.0%), but worse low-temperature performance. Following a comprehensive consideration of performances, the reasonable dosage range of E-HVM modifier is 12 wt% to 16 wt%.

Microstructure and Phase Evolution of Ti-Al-C-Nb Composites Prepared by In Situ Selective Laser Forming.

In the present work, a novel Ti-Al-C-Nb composite was prepared using in situ selective laser forming (ISLF). The formation mechanism of the Ti-Al-C-Nb bulks, which were synthesized using elemental titanium, aluminum, and carbon (graphite) powders via ISLF techniques, was investigated. The results showed that the Ti3Al and TiC phases were the dominant synthesis products during the chemical reactions, and these occurred during the ISLF process. The size of the fine nanoscale crystal TiC grains could reach 157 nm at an energy level of 60 J/mm3. The porous structure of the ISLF specimens was disclosed, and an open porosity of 20–44% was determined via the scanning speed and the laser power. Both the high dynamic viscosity and the reactions of the raw powders led to the generation of a considerable number of pores, whereas the specimen processed using 45 W and 100 mm/s possessed the lowest degree of open porosity.

Effect of ionic liquid on formation of copolyimide ultrafiltration membranes with improved rejection of La3+

Ultrafiltration (UF) as a widely used industrial separation method with optimal selection of membrane materials can be applied to extract rare earth metals from dilute solutions formed during the processing of electronic waste by hydrometallurgical methods. In the present work, promising UF copolyimide membranes were prepared using [hmim][TCB] ionic liquid (IL) co-solvent which can be considered as an environmentally friendly alternative to conventional solvents. The membranes were characterized by ATR-FTIR, TGA, SEM and quantum chemical calculations. A significant difference in morphology of these membranes was revealed by SEM of membrane cross-sections; the P84 membrane has finger-like structure of porous substrate in contrast to spongy structure of substrate for the P84/IL membrane due to a higher dynamic viscosity of the casting solution. The transport parameters were determined in ultrafiltration tests with pure water and an aqueous solution of bovine serum albumin. The addition of ionic liquid to the P84 casting solution increases the performance of the membrane. The rejection capacity was evaluated with respect to La3+ in the form of a lanthanum alizarin complex (LAC) in aqueous acetone solution. The P84 membrane prepared using IL showed a high rejection (98.5%) with respect to LAC, as well as a significant productivity.

The Influence of the Syrup Type on Rheology, Color Differences, Water Activity, and Nutritional and Sensory Aspects of High-Protein Bars for Sportsmen

Most often, high-protein bars consist of a protein preparation in the form of a loose powder, stuck together with a syrup mixture, ensuring a stable mass. According to the legal regulations in force, at least 20% of the energy value must come from protein for the product to be called high-protein. The objective of this study was to evaluate the impact of different syrup sources (oligofructose, maltitol, tapioca fiber, and chickpea-maize fiber) on rheology, water activity, color, and nutritional and sensorial properties of high-protein bars. Texture has changed depending on the type of syrup used. A significant increase of the hardness parameter referring to the control sample was noted for bars containing chickpea-maize liquid fiber in chocolate (311.65 N), with low adhesiveness simultaneously (54.71 N). Samples without chocolate made with the use of oligofructose syrup had apparently higher dynamic viscosities than other bars (226.67 mPas · g/cm3). The water activity of all tested bars indicated the high stability of samples over time (&lt;0.80), except for samples without chocolate made of PM syrup. The color of the tested bars was from light cream to Earth yellow. Bars obtained with tapioca liquid fiber had the lowest nutritional value. Results presented in this study suggest that selecting the correct type of syrup may significantly influence the functional properties of high-protein bars.

The Effect of Type-I Photoinitiators on the Kinetics of the UV-Induced Cotelomerization Process of Acrylate Monomers and Properties of Obtained Pressure-Sensitive Adhesives.

A new method of solvent-free acrylic pressure-sensitive adhesives (PSAs) based on UV-induced cotelomerization products was presented. The key acrylic monomers (i.e., n-butyl acrylate and acrylic acid) with copolymerizable photoinitiator 4-acrylooxybenzophenone in the presence of a selected chain transfer agent (tetrabromomethane, TBM) were used in the UV-cotelomerization process. Moreover, two kinds of UV-photoinitiators (α-hydroxyalkylphenones, HPs and acylphosphine oxides, APOs) were tested. Photo-DSC, viscosity, thermogravimetric, and GPC measurements for cotelomers were performed. The kinetics study revealed that the systems with APOs, especially Omnirad 819 and Omnirad TPO, were characterized by a much higher reaction rate and greater initiation efficiency than HPs systems were. Additionally, the APO-based syrups exhibited a higher solid content (ca. 60–96 wt%), a higher dynamic viscosity (5–185 Pa·s), but slightly lower molecular weights (Mn and Mw) compared to HP syrups. However, better self-adhesive features (i.e., adhesion and tack) were observed for PSAs based on cotelomers syrups obtained using APOs with lower solid contents (55–80 wt%). It was found that as the solids content (i.e., monomers conversion) increased the adhesion, the tack and glass transition temperature decreased and the type and amount of photoinitiator had no effect on polydispersity. Most of the obtained PSAs were characterized by excellent cohesion, both at 20 °C and 70 °C.

Design and optimization of a microneedle with skin insertion analysis for transdermal drug delivery applications

Effectively delivering the drugs through the human skin with less pain and reducing the chance of tissue damage are the main attributes of a microneedle. This paper presents an out-of-plane single silicon carbide (SiC) microneedle having six lumens for drug passing. The total length of the proposed microneedle is about 350 μm with the inner diameter of 30 μm and the outer diameter of 52 μm. COMSOL multiphysics software is used to analyze the performances of the proposed microneedle. The simulated durability of the microneedle is investigated by applying the axial load which generates less stress and deformation. Then, an optimized microneedle tip is designed which reduce pain during insertion. The flow analyses of various viscosity based fluids inside the microneedle are also investigated. Among the selected fluids, the flow of the ibuprofen shows a lowest velocity distribution because of its high dynamic viscosity. The maximum flow rates of ibuprofen are found as 0.01 μL/min and 0.9 μL/min while the inlet pressure are 10 kPa and 100 kPa respectively. On the contrary, a low viscosity fluid such as water provides flow rates of 45.24 μL/min and 433.49 μL/min at same inlet pressures. To verify the performances of our proposed microneedle, a skin model consisting three layers of stratum corneum, epidermis and dermis is designed. Simulation results confirm that the proposed microneedle successfully penetrated the skin model and remains unbroken.

Luminescent Ink Based on Upconversion of NaYF4:Er,Yb@MA Nanoparticles: Environmental Friendly Synthesis and Structural and Spectroscopic Assessment.

NaYF4:Er,Yb upconversion luminescent nanoparticles (UCNPs) were prepared by hydrothermal methods at 180 °C for 24 h. The X-ray diffraction (XRD) and TEM (transmission electron microscopy) images show that the resulting 60 nm UCNPs possess a hexagonal structure. In this work, maleic anhydride (MA) was grafted on the surface of UCNPs to induce hydrophilic properties. The photoluminescence spectra (PL) show upconversion emissions centered around 545 nm and 660 nm under excitation at 980 nm. The luminescent inks, including UCNPs@MA, polyvinyl alcohol (PVA), deionized water (DI), and ethylene glycol (EG), exhibit suitable properties for screen printing, such as high stability, emission intensity, and tunable dynamic viscosity. The printed patterns with a height of 5 mm and a width of 1.5 mm were clearly observed under the irradiation of a 980 nm laser. Our strategy provides a new route for the controlled synthesis of hydrophilic UCNPs, and shows that the UCNPs@MAs have great potential in applications of anti-counterfeiting packing.

Protection of objects from local damage and destruction

The paper deals with the dynamic process of local destruction of an object of armor protection. It is modeled as an object of destruction in the form of a spherical shell, and the threat is represented in the form of a metal round bar. Formulas are given and an estimate of the acceleration rate at which the object of armor protection is guaranteed to lose continuity is made. It is shown that if the rod has a tip covered with a layer of iridium, then under certain conditions, due to the fact that this metal has a high dynamic viscosity under intense loads, the object of armor protection is highly likely to be hit.

Effect of atmosphere on the microstructure and properties of additively manufactured tungsten

The working atmosphere greatly affects the melting and solidification processes in powder-based additive manufacturing. In this work, pure tungsten components were fabricated by selective laser melting (SLM) under argon and nitrogen, respectively. The effects of the atmosphere and processing parameters on densification, microstructures, and phases were investigated. Tungsten processed under nitrogen exhibited a higher density, lower roughness, and superior mechanical performance than that processed under argon. The high dynamic viscosity of liquid tungsten in argon induced balling and pore formation during the laser melting process, leading to relatively low density and poor mechanical properties of the SLM-processed tungsten that was manufactured in argon. The results help to promote the practical application of SLM for complicated tungsten components in the nuclear and military industries.

High-Speed Manipulation of Microobjects Using an Automated Two-Fingered Microhand for 3D Microassembly.

To assemble microobjects including biological cells quickly and precisely, a fully automated pick-and-place operation is applied. In micromanipulation in liquid, the challenges include strong adhesion forces and high dynamic viscosity. To solve these problems, a reliable manipulation system and special releasing techniques are indispensable. A microhand having dexterous motion is utilized to grasp an object stably, and an automated stage transports the object quickly. To detach the object adhered to one of the end effectors, two releasing methods—local stream and a dynamic releasing—are utilized. A system using vision-based techniques for the recognition of two fingertips and an object, as well automated releasing methods, can increase the manipulation speed to faster than 800 ms/sphere with a 100% success rate (N = 100). To extend this manipulation technique, 2D and 3D assembly that manipulates several objects is attained by compensating the positional error. Finally, we succeed in assembling 80–120 µm of microbeads and spheroids integrated by NIH3T3 cells.

Экспериментальное исследование реологических свойств жидкостей для гидроразрыва пласта

The work is devoted to the study of the rheological behavior of proppant carrier fluids used for hydraulic fracturing (HF) technology in order to increase oil recovery, including from hard-torecover oil and gas reserves, in a wide range of deformation rates using viscometers of various designs. Rheological properties were studied for proppant carrier fluids based on guar and Surfogel grade D, (type 70–100, produced by JSC “Polyex”) with comparable shear rate 128 s–1. Quasistatic experiments to determine the values of the dynamic viscosity of the liquids under study were carried out using a falling ball viscometer (according to the Stokes method). Using an original viscometer, consisting of two coaxial cylinders (rotary rheometer), the dynamic viscosity of surfogel was investigated in a wide range of shear rates. The viscoelastic properties of surfactants were studied using a Physica MCR501 rheometer, which has a plane-to-plane measuring system and allows rheological studies in rotational and oscillatory modes. A comparison of the rheological properties of fluids based on the guar and the viscoelastic surfactant is carried out and it is established that a fluid based on the viscoelastic surfactant has a higher dynamic viscosity and does not lose its elastic properties, which is an certain advantage over a fluid based on the guar.