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Background: Cryotherapy is a physiotherapy method used to treat back pain in older persons., Objective: This study aims to evaluate the changes in the rheological parameters of blood in older women with spondyloarthrosis, who underwent whole-body cryotherapy., Methods: The experimental group comprised 69 older women with lumbar spondyloarthrosis, aged between 65 and 70 years. Due to the methodology of the procedure, the experimental group was randomly divided into three groups. Each group underwent two weeks of different types of physiotherapy: only whole-body cryotherapy (22 women); only kinesitherapy (23 women); and both cryotherapy and kinesitherapy (24 women). The control group comprised 25 women who did not undergo any form of therapy. The evaluation of the rheological properties of the blood encompassed measurements of the plasma viscosity, the erythrocyte elongation and aggregation indices, and the level of fibrinogen., Results: The conducted rheological tests revealed a significant decrease in the erythrocyte elasticity and aggregation indices only in the group of women who had undergone both whole-body cryotherapy and kinesitherapy., Conclusions: Applying whole-body cryotherapy to older women with spondyloarthrosis decreases the elasticity of erythrocytes and, despite favourable changes in the aggregation parameters, problems with perfusion may still appear. For this reason, the benefit of using whole-body cryotherapy in these persons is debatable.

In the context of the "dual carbon" goal, in order to solve the problem of high value utilization of modified magnesium and coal-based solid waste resources and efficient storage of carbon dioxide, CO2 gas was introduced into the modified magnesium-coal based solid waste backfill material under normal temperature and pressure conditions to prepare a new type of solid waste carbon fixation backfill material (CO2-MCSB). The preparation and flow performance study of CO2-MCSB provides a new technological approach combining solid waste resource utilization and CO2 storage, which can provide new theoretical references for solid waste backfill in mines. The effects of stirring rate, stirring time, and aeration rate on its fluidity and rheological properties were investigated through micro slump, rheological testing, and microstructure testing. The research results indicate that: (1) the slump range of freshly mixed CO2-MCSB slurry is 125 ~ 146 mm, and the expansion range is 9.5 ~ 39.5 cm, fully meeting the requirements of mine backfill fluidity. (2) The newly mixed CO2-MCSB slurry exhibits swelling fluid, and after ventilation, there is a significant thickening phenomenon, resulting in a significant decrease in flowability. (3) Microscopic analysis shows that the calcium carbonate generated by the carbonation reaction of the slurry after aeration fills the gaps, thereby increasing the probability of collision between internal particles and increasing the critical resistance for flow to begin. (4) There is a significant linear relationship between the flowability and rheological parameters of freshly mixed CO2-MCSB slurry, showing a negative correlation. (5) In the backfill application process, the stirring rate of 200 r/min, the aeration stirring time of 5 min, and the aeration rate of 5 L/min can be controlled to achieve good flow performance of CO2-MCSB. [ABSTRACT FROM AUTHOR]

A high-density water-based drilling fluid (WBDF) is crucial for maintaining wellbore stability, controlling formation pressures, and optimizing drilling performance in challenging subsurface conditions. In the present research, the effect of micronized calcium carbonate (calcite), extracted from the Aruma formation outcrop, is evaluated as one of the additives that could be added to the ilmenite-weighted WBDF to enhance and optimize its properties. Various concentrations of Calcite microparticles were introduced into identical fluid formulations to assess their impact. The concentrations ranged from 0, 10, 20, to 30 lb/bbl, providing a comprehensive examination of the effects of calcite microparticles across a spectrum of concentrations within the fluid. The results highlighted that adding Barite microparticles to the WBDF revealed a notable enhancement in rheological properties. Specifically, the yield point demonstrated an increase of 37%, 37%, and 11% for concentrations of 10, 20, and 30 lb/bbl of calcite, respectively. Equally significant, high-pressure-high-temperature (HPHT) filtration analysis indicated a considerable enhancement for the fluids containing calcite microparticles. A reduction of 14.5%, 24.6%, and 13% were observed in HPHT filtrate for concentrations of 10 lb/bbl, 20 lb/bbl, and 30 lb/bbl respectively. Simultaneously, there is a reduction in filter cake thickness by 20%, 40%, and 20%, respectively. No ilmenite settling was observed in the sample containing 20 lb/bbl of calcite, unlike the other concentrations. These diverse results strongly suggest that the optimal concentration for calcite microparticles is 20 lb/bbl. The combined utilization of the optimal concentration of calcite microparticles alongside the established additives proves to be an effective strategy for optimizing the ilmenite-weighted WBDF performance in terms of both thermal stability and rheological behavior. [ABSTRACT FROM AUTHOR]

The reduction in the rheological parameters and dissolution rate of precursors in geopolymer coatings during early hydration significantly contributes to sagging. This study aims to improve the sag resistance of these coatings by incorporating diatomite filler. Rheological testing was conducted to assess the impact of diatomite and its concentration on the yield stress, plastic viscosity, and thixotropy of the geopolymer coatings. The results indicated that diatomite's large specific surface area and high reactivity have a significant influence on the rheological parameters and early dissolution rate of precursors. With a diatomite concentration of 1.1%, the coating exhibited a yield stress of 2.749 Pa and a plastic viscosity of 0.921 Pa·s, maintaining stability, homogeneity, and no sagging at a thickness of 600 μm. Furthermore, the highly active SiO2 in diatomite participates in the secondary hydration reaction of the geopolymer materials led to the formation of substantial C-(A)-S-H gel. This gel enhances internal interconnectivity within the coating, thereby improving its rheological and mechanical properties. [ABSTRACT FROM AUTHOR]

In rheological testing, different test regimes can result in large differences in the rheological curves, and the pre-shear procedure is one of the most important parts of the test. In order to investigate the effect of the pre-shear regime on the rheological properties of cement pastes, an Anton Paar 102 rotary rheometer was used for the test. Two different pre-shear regimes (RF and CP pre-shear), three different pre-shear duration times (50 s, 100 s, 150 s), and four different pre-shear rates (25 s-1, 50 s-1, 100 s-1) are carried out for the test. The results showed that with the increase of pre-shear duration or rate, the four rheological parameters (plastic viscosity, yield stress, rheological index, and thixotropy) of the pastes decrease in different degrees. RF pre-shear was more influenced by shear time, while CP pre-shear was influenced by shear time and rate. The pre-shear regimes led to different changes in the flocculation structure of the cement paste, which had a great influence on rheological parameters ultimately. Based on the improved Krieger-Dougherty model, the effective solid volume fraction of cement paste was calculated. Analysis shows that the phenomenon of "deflocculation" and "re-flocculation" occurs when the cement paste is subjected to shear action, thus, the pre-shear regimes destroy the structure of the pastes. With the increase of pre-shear duration or rate, the effective volume fraction decreased, which indicated that the initial flocculation structurewas broken. The greater the damage degree of pre-shear, the slower the establishment rate of the internal structure of the pastes in dynamic shear, resulting in lower rheological parameters. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental studies on the effect of multi-walled carbon nanotubes (MWCNTs) additives on the viscosity and rheological characteristics of drilling emulsions based on mineral oil. The formulations of typical drilling fluids containing 65% hydrocarbon phase were modified with nanotubes. The mass concentration of nanotubes in emulsion varied from 0.1 to 0.5%. The formulation and method of preparing stable drilling emulsions with MWCNT additives have been proposed. The rheology of drilling emulsions modified with MWCNTs was studied. The dependency of rheological characteristics on the nanotubes concentration was obtained. In general, MWCNT additives can significantly alter the rheological characteristics of drilling hydrocarbon emulsions at lower concentrations compared to the additives in the form of spherical nanoparticles. This is very important for their practical use in industry. The optimal concentration of MWCNTs for controlling the rheological properties of drilling emulsions is about 0.25 wt. %. [ABSTRACT FROM AUTHOR]

The Anton Paar MCR 52 intelligent high-speed rheometer was utilized in this paper to conduct rheological tests on the Jiangjiagou debris flow slurry via linear loading. The relationship curves between shear rate and shear stress at different solid volume concentrations were obtained, and predictive formulas for yield stress and viscosity coefficient variations with the shear rate are proposed. Furthermore, the evolution mechanisms of yield stress and viscosity coefficient with changes in solid volume concentration of the debris flow were thoroughly analyzed. The results indicated that the rheological curves of the Jiangjiagou debris flow conformed to the Bingham fluid model. An increase in solid volume concentration continuously promoted the upward trend of the rheological curves, with significant increments observed only at high volume concentrations. A predictive model for debris flow rheological parameters was established based on the linear relationship between the rheological parameters and the solid volume concentration. The rise in solid volume concentration inhibited turbulence in the debris flow, while clay minerals enhanced the debris flow slurry's ability to capture pore water. Significant shear-thinning effects were observed within the debris flow, which were particularly more pronounced at lower shear rates. The study outcomes hold crucial engineering significance for a better understanding of debris flow rheological properties, the calculation of debris flow dynamic parameters, and disaster prevention and control. [ABSTRACT FROM AUTHOR]

Fatigue failure in asphalt pavements, caused by continuous loading, primarily occurs at the interface between the asphalt binder and the aggregate (adhesive failure) or within the asphalt binder itself (cohesive failure). This study conducted variable stress fatigue tests on asphalt binders to investigate the fatigue damage evolution mechanism that aligns most closely with actual road conditions. By altering test conditions such as stress amplitude and loading frequency, the study summarized the patterns of change in the fatigue performance parameters of binder samples and analyzed their fatigue life. The research methods employed are of significant value for refining the existing asphalt fatigue evaluation systems. Indicators such as dissipated energy ratio, cumulative dissipated energy ratio, rate of change in dissipated energy, and the G-R constant n × Gn* were used as criteria for fatigue failure. The fatigue life of samples under different stress levels was calculated, and the applicability of each dissipated energy fatigue indicator was evaluated. The evaluation indicators, like dissipated energy ratio and cumulative dissipated energy ratio, failed under large stress outside the non-linear viscoelastic range, whereas the rate of change in dissipated energy and the G-R constant n × Gn* accurately determined the fatigue life of samples in fatigue tests at all stress levels, covering a broader range of applicable stresses. In variable stress fatigue tests, the rate of change in dissipated energy and the G-R constant were used as indicators for determining fatigue failure. Under a small-to-large loading mode, the second stage of the sample's fatigue life was too short, causing the G-R constant curve to not reach its peak, and hence it could not accurately determine the sample's fatigue life. Under a large-to-small loading mode, there are sufficient loading cycles before fatigue failure occurs, allowing the G-R constant curve to reach its peak, demonstrating that the G-R constant remains applicable in this loading mode. Under both small-to-large and large-to-small loading modes, the fatigue failure point of the samples could be determined based on the rate of change in dissipated energy curve. It is recommended to use the rate of change in dissipated energy as the failure criterion for samples in variable stress fatigue tests on asphalt binders. [ABSTRACT FROM AUTHOR]

Three types ol water reducers, namely polycarboxylate superplasticizer, melamine super plasticizer, and naphthalene superplasticizer, were used in this study to test the fluidity, rheology, and strength ol backlill at different dosages ol water reducer. The effects ol water reducer type and dosage on the Iluidity, yield stress, plastic viscosity, apparent viscosity, thixotropy, and strength ol the backlill were studied. Research result showed that adding a water reducer can significantly improve slurry's Iluidity, and reduce yield stress and apparent viscosity. The effect ol water reducer on the plastic viscosity ol slurry was relatively small. In addition, the thixotropy ol slurry increased firstly and then decrease with the increase of water reducer content Compared with melamine superplasticizer and naphthalene superplasticizer, polycarboxylate superplasticizer has a more noticeable imp rovemen t ellect on slurry Ilowability. At a certain concentration, adding a water reducer will reduce the early strength ol the backlill, but it has a small impact on the strength ol the backlill in the middle and later stages, even slightly increased. [ABSTRACT FROM AUTHOR]

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Non-Newtonian fluids are commonly used in a wide range of industries; one example are in biogas power plants. Proper measurements and modeling of such fluids can be crucial from the design and operations point of view. Results presented in this study covered seven samples from three plants (a sewage sludge treatment plant, utilization biogas station and a biogas plant in a sugar factory), including mechanically thickened excessive activated sludge (MTEAS), sugar beet pulp (SBP), liquid fruit and vegetable waste (FVW), beet roots (BR) and corn waste (CW); their mixtures were prepared as in a real plant. The total solid content remained below 6.8% for all samples. The apparent viscosity (15 RPM) did not exceed 10 Pas in any sample. A correlation analysis for solvent type influence on the viscosity was carried out. The obtained results were analyzed, and the Herschel–Bulkley rheological model was selected for the fluid description. Then, the Moullinex method was applied to determine the H–B model parameters. The obtained results may contribute to the proper design and operation of various biogas power plants, in which viscosity seems to be one of the crucial flow parameters that influences the device types used, as well as energy consumption. [ABSTRACT FROM AUTHOR]

The distribution of the flow field, the input energy of the twin‐screw, and the dissipated energy on the fluid during the twin‐screw extrusion process were calculated by the POLYFLOW software to establish the relationship between the rheological parameters of starch fluid and tensile properties of the final extrudate. The results demonstrated that the pressure difference, the input energy of the twin‐screw, and the dissipated energy on the fluid were directly proportional to the zero‐shear viscosity (η0), reduced with the raise of the relaxation time constant (λ) and raised with the raise of the power‐law index (n). When the moisture content of starch fluid raised, the η0 value reduced, whereas the λ value and n value increased. The pressure difference, the input energy of the twin‐screw, and the dissipated energy on the fluid decreased, reducing the maximum tensile force of the final extrudate. Through numerical simulation and experimental verification, it was found that the changes of η0 value, λ value, and n value restricted each other on the tensile properties of final extrudate. Based on the numerical simulation, the tensile properties of the final extrudate could be predicted through rheological parameters of starch fluid. Practical Applications: A method was established to predict the final extrudate properties based on rheological parameters and numerical simulation in this study. Based on the numerical simulation, the tensile properties of the final extrudate could be predicted through rheological parameters of starch fluid. This research will provide insight into the mechanism of twin‐screw extrusion of starch‐based materials. [ABSTRACT FROM AUTHOR]

Film-forming solutions based on four types of biopolymers were prepared and their rheological properties were determined. High methylated apple pectin and sodium alginate were used at the concentrations 1%, 1.5%, and 2%, whereas soy protein isolate and pork gelatin were obtained at 4%, 8%, and 12%. The parameters determining the production of the appropriate type of packaging film or edible coating are the setting time on the substrate, regardless of its type, and the gelation temperature, which were analyzed in the study by determination of flow curves and rheological parameters of prepared dispersions. The Newtonian model was used to describe the flow curves of the gelatin and sodium alginate solutions, while the Ostwald–de Waele model was used to describe the flow curves of the soy protein isolate and high methylated apple pectin solutions. The apparent viscosity of all solutions increased with increasing biopolymer concentrations, from 0.0042 to 0.0061 Pa·s and from 0.0187 to 0.0884 Pa·s for high-methylated apple pectin and sodium alginate, respectively; whereas, for a protein-based solution the viscosity increase was from 0.024 to 0.100 Pa·s and from 0.0018 to 0.0056 Pa·s for soy and gelatin, respectively. Modulus of elasticity curves appeared only at the highest concentrations, which means that the formation of the continuous structure of film or coating occurs by different mechanisms depending on the biopolymer type and its amount dispersed in aqueous solutions. [ABSTRACT FROM AUTHOR]

In this study, the usability of colemanite wastes (CW), in mortar mixtures, was examined in terms of compressive strength, while at the same time it was aimed to evaluate the effects of this waste on the rheological properties of mortar and paste mixtures. Mortar and cement paste mixtures were produced by substituting 1, 3, 5, and 7% of the cement with the CW. Marsh-funnel flow times, mini-slump values, rheological parameters, and setting times of cement paste mixtures containing CW were determined. The time-dependent slump-flow and 1-, 7-, 28-, and 56-day compressive strength values of the mortar mixtures were determined. The microstructures of the specimens were evaluated by using SEM images, and phase analyses were examined with XRD analysis. The results showed that the use of CW negatively affected the fresh state properties and rheological parameters of cementitious systems. However, CW addition decreased the 1-, 7-, and 28-day compressive strength. Only a slight increase was observed in the strength of mixtures containing 5 and 7% CW at 56 days. [ABSTRACT FROM AUTHOR]

During well drilling in offshore conditions beyond the North of the Arctic Circle, there are often problems associated with deviations in the rheological parameters of the drilling mud as the temperature changes. Mud temperature in the upper part of the well in most cases is in the range up to 20 °C, whereas in the productive formation it is up to 80 °C and more. For such conditions, it is necessary to estimate the influence of temperature on the rheological parameters of drilling fluids, which is done in this paper. Compositions of water-based and hydrocarbon-based muds that may be used in the conditions of the offshore hydrocarbon fields were considered. The paper presents the authors' formula for a drilling mud that possesses more stable rheological parameters in the temperature conditions of the offshore oil field and is more environmentally friendly. The physical properties of the newly designed drilling mud were measured with laboratory equipment. Rheological investigations were carried out under varying temperatures up to 80 °C. The results of the experiments show the newly designed drilling mud to be more stable than its hydrocarbon-based analogue. Besides, the newly developed composition has a lower content of solid phase, which is also an important parameter for the process of sea wells construction, often characterized by a narrow window of permissible pressure. [ABSTRACT FROM AUTHOR]

Background: Magneto-Rheological (MR) fluids are made—up of iron particles suspended in carrier liquid containing additives in proportion to make reversible changes to the whole suspension rheological properties (apparent viscosity, shear stress). MR dampers have generated a lot of interest amongst researchers in the last few decades because of their fast response and mechanical simplicity as compared to active dampers. Aim: The work presents a systematic approach to the design and development of a low-cost optimal MR damper, wherein the focus is on optimizing geometrical features of the annular valve along with the electric current of the MR damper by using the Taguchi approach. Method: The MR damper was manufactured and experimentally tested to observe its effect on damping performance. Force transmissibility and damping ratio are important parameters for road handling and ride comfort. Results: It was found that implementing in-house prepared low-cost MR fluid in MR damper application results in damping force and damping coefficient increase as current intensity increases. It has been also observed that the resultant force transmissibility magnitude at 1.5A is less compared to the passive damper due to the high damping coefficient. Conclusions: Hence, concluding that MR damper based on low-cost MR fluid in the present study has better damping force performances as compared to passive dampers. It might also assist to improve the handling and comfort of passenger vehicles. The experimental results have been compared with Nagler's fresh modified Bingham model (analytic approximation) formulation (apparent viscosity and shear stress) and literature references. A qualitative and quantitative agreement was found between Nagler—Bingham generalized model (analytic approximation) and experimental results for the examined rheological parameters (apparent viscosity and the developed shear stress). Also, a full-scale qualitative agreement was found between the experimental and analytic results (shear stress, apparent viscosity, damping force, damping coefficient, etc.) and the various distinguished literature references. [ABSTRACT FROM AUTHOR]

Non-Newtonian fluids are commonly used in a wide range of industries; one example are in biogas power plants. Proper measurements and modeling of such fluids can be crucial from the design and operations point of view. Results presented in this study covered seven samples from three plants (a sewage sludge treatment plant, utilization biogas station and a biogas plant in a sugar factory), including mechanically thickened excessive activated sludge (MTEAS), sugar beet pulp (SBP), liquid fruit and vegetable waste (FVW), beet roots (BR) and corn waste (CW); their mixtures were prepared as in a real plant. The total solid content remained below 6.8% for all samples. The apparent viscosity (15 RPM) did not exceed 10 Pas in any sample. A correlation analysis for solvent type influence on the viscosity was carried out. The obtained results were analyzed, and the Herschel–Bulkley rheological model was selected for the fluid description. Then, the Moullinex method was applied to determine the H–B model parameters. The obtained results may contribute to the proper design and operation of various biogas power plants, in which viscosity seems to be one of the crucial flow parameters that influences the device types used, as well as energy consumption.

This research critically analyzes the crucial elements of Dye-Sensitized Solar cells (DSSCs), concentrating on the detailed rheological behaviors of component materials and the vital roles of modeling, simulation, and electrical modeling in improving DSSC technology. The variation in rheological characteristics of semiconductor films, counter electrodes, dyes, and electrolytes used in DSSC manufacturing, emphasizes the complex aspect of DSSC research. The examination of rheological characteristics such as shear stress, viscosity and the shear rate at which a liquid is being sheared also forms an important milestone in capturing material behavior. Rheology becomes critical for really telling apart different properties such as pseudoplastic, dilatant or thixotropic behavior. Understanding these basic properties is of extremely high importance, for they directly determine how substances react to external force and deformation. These parameters are like a doorway, providing deep insight into the intricate processes of flow mechanics and resultant changes in structure. Furthermore, modeling and simulation approaches used to uncover the intricacies of DSSC functioning are critically assessed, encompassing elaborate electrical models, mathematical frameworks, and photovoltaic simulations that unveil the dynamic interaction of components within DSSCs. A deeper understanding of DSSC technology and its potential in the realm of renewable energy is facilitated by the critical analysis of these essential aspects. • DSSCs represent a promising pathway for environmentally conscious energy generation. • Rheological analysis in DSSC materials uncovers non-Newtonian behaviors, pivotal for optimizing components and overall photovoltaic efficiency. • Temperature and light intensity impact DSSC rheology and performance, necessitating modeling for real-world conditions. • Electrical modeling is critical for optimizing DSSC efficiency, where parameters such as series resistance, ideality factor, and recombination constants significantly impact photovoltaic outcomes. • Addressing DSSC commercialization hurdles necessitates meticulous rheological control and advanced characterization, multi-scale modeling, and interdisciplinary collaborations to harness their renewable energy potential. [ABSTRACT FROM AUTHOR]

Highlights • There are good correlations between chemical and physical-rheological parameters of RAB-containing binder mixes. • Colloidal index is a good indicator for estimating superpave fatigue parameters. • Rejuvenator improved fatigue performance of the RAB to the level of that of the control binder mix. • Rejuvenator improved colloidal index of the RAB to the level of that of the control binder mix. Abstract Bitumen extracted from reclaimed asphalt pavement (RAP) materials is known as reclaimed asphalt binder (RAB). Many studies have been conducted to evaluate effect of the rejuvenating agents in physical-rheological and chemical properties of the RAB. The aim of this study is to evaluate the effects of other modifiers such as soft bitumen and polymer modified bitumen (PMB) in performance of RAB-containing asphalt binders in comparison with rejuvenators. In this study, changes in physical-rheological parameters and chemical structure of RAB-containing binder mixes were investigated by different modifiers including softer bitumen, rejuvenator and the waste polymer modified bitumen (WPMB). Penetration, softening point, rotational viscosity, dynamic shear rheometer (DSR), saturates, aromatics, resin and asphaltenes (SARA) fractionation, Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) tests were performed for this purpose. Results showed that the rejuvenator and softer bitumen had the greatest effect on the improvement of the physical-rheological and chemical properties of the RAB-containing binder mixes, respectively. So that, the rejuvenator, softer bitumen and the WPMB improved fatigue resistance and chemical structure of the RAB-containing binder mixes to the level of that of the virgin binder when the RAB content was limited to 100%, 50% and 30% RAB, respectively. Moreover, results indicated that there are good correlations between chemical and physical-rheological parameters. Meanwhile, colloidal index of the binder mixes was a good indicator for estimating the superpave fatigue parameters of asphalt binders. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of particle size on rheological properties is greater than that of particle shape. • Rheological parameters of small particle size is obviously affected by shear rate and time. • Yield stress obtained by Bingham model and Herschel-Bulkley model are the highest and lowest, respectively. • Plastic viscosity obtained by Bingham model is lower than that obtained by Modified Bingham model. • Rheological index (n) of Herschel-Bulkley model can well characterize the shear thinning degree. With the continuous development of mineral admixtures and additives, the influence of various factors on the rheological properties of cement-based slurry remains unclear. In this study, the effects of particle size, particle shape, shear rate, and time on the rheological properties were analyzed. The rheological curves were determined using an RST-SST rheometer and fitted with the Bingham model, Modified Bingham model and Herschel-Bulkley model, respectively. The rheological parameters were evaluated. The results showed that the effect of particle size on the rheological properties is much greater than that of the particle shape. The small particle size is evidently affected by the shear rate, and the rheological parameters increase with time. The three rheological models can well describe the samples containing microfine cement (MC), fly ash (FA) and calcium carbonate whisker (CaCO 3 whisker). The sample containing nano-silica (nano-SiO 2) requires special analysis. The yield stress predicted by the Bingham model is the highest, whereas that predicted by the Herschel–Bulkley model is the lowest. The plastic viscosity predicted by the Bingham model is lower than that predicted by the modified Bingham model. The rheological index (n) of the Herschel–Bulkley model can effectively characterize the degree of shear thinning. The three rheological models demonstrate their characteristics and advantages, and an appropriate rheological model should be selected to evaluate the rheological parameters according to the requirements. The research aims to provide theoretical support for the analysis of rheological properties and the selection of rheological models. [ABSTRACT FROM AUTHOR]

[Display omitted] • The rheological parameters of the test group first decrease and then increase. • The rheological parameters obtained by different operating modes vary greatly. • The operating mode of step change is considered as the optimal mode of rheometer. An appropriate amount of air-entraining agent improves the wet shotcrete fluidity, and the accurate measurement of rheological parameters accurately expresses the rheological characteristics of sprayed concrete. In this paper, eBT2 rheometer was used to measure time variation of rheological parameters of high air content wet shotcrete (HACWS). At the same time, in order to investigate measurement accuracy of shotcrete rheology, the influence of rheometer operating modes (OM) on rheological parameters was studied. This paper selected four rheometer OM to comprehensively analyze the rheological characteristics and rheometer measurement accuracy of HACWS. The results showed that relative plastic viscosity (RPV) and relative yield stress (RYS) of HACWS both tended to decrease first and then increase with time. The torque measured by eBT2 rheometer remained constant at high shear rates. The rheological parameters obtained with different OM differed significantly, and OM-B was recommended to analyze the rheological properties of fresh concrete. This paper provides a reference for the selection of air-entraining agent type and rheometer OM. [ABSTRACT FROM AUTHOR]

[Display omitted] • ML predicts rheology, workability, and mechanical strength of SCC with high accuracy. • Integration of SHAP and PDP with ML ensures predictions are physically sensible. • The proposed models analyzed how SCC composition affects its properties by changing rheology. • SF, L-box ratio, and segregation rate were negatively correlated with YS and PV. • V-funnel time and mechanical strength were positively correlated with YS and PV. • The dependence of segregation rate on the YS was stronger at a relatively low YS. Self-Compacting Concrete (SCC) has gained significant popularity due to its exceptional workability performance. However, designing SCC poses more challenges than ordinary concrete, as it must fulfill requirements for filling ability, passing ability, and segregation resistance. Regrettably, existing test techniques lack the ability to simultaneously evaluate all these properties, and relying on experiential knowledge and cognition without tangible physical meaning. Although rheology examines the flow and deformation of fluid materials and is closely related to SCC's properties, the relationship between SCC composition, rheology, and properties remains unclear due to the complexity of the factors involved and the absence of effective tools. This study introduces a novel approach by utilizing a random forest algorithm to create multiple interpretable machine learning models for predicting the rheology, workability, and mechanical properties of SCC. Additionally, SHapley Additive exPlanation (SHAP) and Partial Dependence Plot (PDP) methods were integrated with the models to analyze how SCC composition impacts its properties by altering the rheology of the mixture. The models exhibit high accuracy in predicting both rheology and SCC properties (R2 = 0.93 ∼ 0.98, Index of Agreement = 0.92 ∼ 0.99). According to the SHAP and PDP analysis, yield stress and plastic viscosity were negatively correlated with slump flow, L-box ratio, and segregation rate, while exhibiting a positive correlation with V-funnel time and strength. Furthermore, the dependence of the segregation rate on yield stress was observed to be stronger at relatively low yield stress levels (below 40 Pa). These models provide valuable insights for designing and evaluating SCC mixtures tailored to specific requirements. Additionally, the study explores underlying mechanisms and offers guidelines for proportioning SCC in different design scenarios. The findings contribute to the advancement of SCC technology and have significant implications for the construction industry. [ABSTRACT FROM AUTHOR]

The cuttings transport was numerically simulated based on kinetic theory of granular flow in combination with sliding mesh for drill pipe rotation in the horizontal well. The Herschel-Bulkley (H-B) model was implemented to describe the rheological behavior of drilling mud. Three distinguishable flow regions of cuttings and swaying phenomenon of cuttings distribution along the direction of drill pipe rotation were observed. The granular temperature of cuttings is high near the wall of drill pipes, which indicates that the energy from the rotating drill pipe is transferred to cuttings. Effects of three rheological parameters ( τ 0 , K HB and n ) on the flow behavior of cuttings and H B fluid were analyzed. With the increase of Herschel-Bulkley fluid rheological parameters, the height of cuttings bed decreases, and the axial flow of cuttings at the lower side is significantly enhanced, but the pressure drop through the annulus is increased. When the value of consistency coefficient and flow behavior index of H-B fluid is low, the cuttings transportation in the wellbore is unstable with the pulsation of cuttings volume fraction in the annulus. Among the three rheological parameters, the flow behavior index plays the most significant role in pressure drop through the annulus. [ABSTRACT FROM AUTHOR]

[Display omitted] • Olefin emulsions with a saturated CaCl 2 solution exhibit high stability. • Olefin emulsions with a saturated NaCl solution require less emulsifier; • Saturated NaCl solution is the most proper choice to compose the non-aqueous fluids; • Olefin emulsions with a saturated CaCl 2 solution show high thixotropy. Drilling fluids continue under development, being a challenge for the oil industry, which attempts to optimize technical performance, to comply with environmental laws, and to reduce fluid costs. A non-aqueous based drilling fluid widely used by Petrobras has been reformulated due to changes in Brazilian environmental legislation. The paraffinic base of the drilling fluid was replaced by an olefinic base, which is more biodegradable. Hence, to improve drilling fluid performance, the characteristics of olefin emulsions formulated with saturated NaCl and CaCl2 solutions were investigated. Therefore, for different emulsifier concentrations and stirring speeds, the droplet size distribution, the stability, and the rheological parameters of three emulsions were evaluated. All these emulsions had distinct dispersed phases, being these saturated solutions of NaCl, CaCl2, and 75% NaCl and 25% CaCl2. The increase of the stirring speed was followed by the emulsified systems apparent viscosities increase, but their polydispersity index and D 50 values were reduced. The NaCl/Olefin emulsion exhibited lower stability, apparent viscosity, and emulsifier saturation concentration when compared to the CaCl2/Olefin emulsion. Besides, the CaCl2/Olefin emulsion showed more pronounced thixotropic behaviour. [ABSTRACT FROM AUTHOR]

The article deals with thermal and rheological properties of two selected biooils (PL 64S - sample No. 1, and PL 04N - sample No. 2). For thermal parameters measurements, Hot wire method was used, for detection of rheological parameters rheometer Anton Paar MCR 102 was used and the density was measured by densimeter DM 40. For both biooil samples, two series of thermophysical parameters measurements were made. In the first series thermal conductivity and thermal diffusivity were measured at constant laboratory temperature. The second series was focused on identification of thermophysical parameters changes during temperature stabilisation. The parameters as dynamic viscosity, kinematic viscosity and density were measured in the temperature range (20-50°C). For samples with constant temperature basic statistical characteristics were calculated - standard deviation and probable error in %. For relations of thermal and rheological parameters to temperature nonlinear dependencies were obtained. The polynomial functions of the second degree were used for thermal parameters and exponential functions for rheological parameters. [ABSTRACT FROM AUTHOR]

The present work had as objective to establish mathematical models that allow the prognosis of the Theological parameters of the lateritic pulp at concentrations of solids from 35% to 48%, temperature of the preheated hydromixture superior to 82 ° C and number of mineral between 3 and 16. Four samples of lateritic pulp were used in the study at different process locations. The results allowed defining that the plastic properties of the lateritic pulp in the conditions of this study conform to the Herschel-Bulkley model for real plastics. In addition, they show that for current operating conditions, even for new situations, UPD mathematical models have a greater ability to predict rheological parameters than least squares mathematical models. [ABSTRACT FROM AUTHOR]

An only suitable type of self-compacting recycled concrete (SCRC) for all applications does not exist, as happens with conventional self-compacting concrete (SCC). An experimental program was carried out to evaluate workability and rheology of 49 mixes of self-compacting concrete made replacing the natural coarse aggregate by recycled concrete coarse aggregate. Workability responses included the slump flow, L-box, J-Ring and sieve segregation tests. The suitability of the limits fixed with these tests for the usual applications in SCC was discussed for SCRC. Rheological responses included the stress growth and flow curve tests. Both workability and rheological responses were compared to indicate relationships between them and in order to observe if they follow the same trend in SCRC as in conventional SCC. Finally, a workability box was proposed to describe recommended combinations of both static yield stress and plastic viscosity for SCRC at 15 min from the cement-water contact, taking into account the fulfilment of several workability limits. Also, a second box was defined at 45 min to describe the time-dependent evolution of the first one. [ABSTRACT FROM AUTHOR]

Dispersion of the generalized Rayleigh waves propagating in a covered halfspace made of viscoelastic materials is investigated by utilizing the exact equations of the theory of linear viscoelasticity. The dispersion equation is obtained for an arbitrary type of hereditary operator of the materials of the constituents and a solution algorithm is developed for obtaining numerical results on the dispersion of the waves under consideration. Dispersion curves are presented for certain attenuation cases and the influence of the viscosity of the materials is studied through three rheological parameters of the viscoelastic materials which characterize the characteristic creep time, long-term values and the mechanical behaviour of the viscoelastic material around the initial state of the deformation. Numerical results are presented and discussed for the case where the viscoelasticity of the materials is described through fractional-exponential operators by Rabotnov. As the result of this discussion, in particular, how the rheological parameters influence the dispersion of the generalized Rayleigh waves propagating in the covered half-space under consideration is established. [ABSTRACT FROM AUTHOR]

The effect of cement fineness on the fresh state and rheological properties as well as compressive strength of cementitious systems was investigated. A CEM I 42.5R portland cement containing 7.92% C3A and sulfate resisting cement containing 3.58% C3A were used. The cements were ground to 4 different Blaine finenesses, ranging from 2800 to 4500 cm2/g. In the absence of water-reducing admixture, the water requirement of mixtures increased with an increase in the cement fineness. Thus, the fresh state properties of the mixtures were affected negatively. However, surprisingly, a reverse behavior was observed in the mixtures containing water-reducing admixtures, that is, an increase of the cement fineness increased the effectiveness of the admixture; consequently, the fresh state properties of the mixtures were improved. This seems to have been caused from the higher adsorption of the admixture on finer cement grains than on the coarser particles. Moreover, as expected, the strength of the mortar and concrete mixtures increased along with the increase in cement fineness and its C3A content. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the effect of methylcellulose and carboxymethylcellulose on the rheological properties of hydrogels applied to skin on chitosan in the presence of the additives propylene glycol and glycerol. Rheological studies showed that the tested gels are non-newtonian systems, and have thixotropic properties. Substrates made of methylcellulose and chitosan are characterised by higher shear values than those obtained with carboxymethylcellulose. The addition of polymers had a positive influence on the dispersion of hydrogels, and the addition of excipients increased firmness, consistency and cohesiveness of the gels. Larger increases were observed with the addition of 10% of glycol propylene and glycerol contents for methylcellulose and of 20% of carboxymethylcellulose. [ABSTRACT FROM AUTHOR]

The study was performed to examine whether the chemical composition of processed meats can be identified based on their rheological properties. The analyzed material comprised ten types of pork and poultry cold cuts supplied by renowned manufacturers and available throughout Poland. The rheological properties of cold cuts were derived using a nonlinear rheological model and correlated with the results of proximate chemical analysis. An analysis of processed meats did not show correlations between variations in their rheological properties and proximate chemical composition versus production date. However, the results of proximate chemical and rheological analyses supported the identification of the evaluated products. Both methods produced similar results only when the type of product or raw materials were known. The rheological properties of the analyzed processed meat products supported the identification of their protein, ash and dry matter content, but could not be used to estimate their collagen and fat content with satisfactory precision. Practical Applications The manuscript presents an attempt to develop a mathematical model describing the rheological properties of the analyzed material, including the elastic modulus, consistency index, flow index and flow limit, which are not dependent on the stress relaxation tests used to establish those values. We also described an approach to the identification of protein, ash and dry matter content of sausages based on rheological data, and correlations between rheological/mechanical measurements and the chemical composition of meat products. The indirect method for identifying the proximate chemical composition of processed meat products based on their rheological properties poses an alternative to laborious and time-consuming analytical techniques, and it can be used to design a simple measuring device. The proposed methodological approach can have important implications for both industrial practice and research. [ABSTRACT FROM AUTHOR]

In this paper magnetic organic-inorganic hybrid membranes based on EC, PPO polymer matrices and various magnetic powder microparticles were synthesized and studied. Constant pressure permeation technique and the Time Lag method were used to obtain the gas transport coefficients. The mechanical, rheological and magnetic parameters of magnetic hybrid membranes were examined. It was found that their separation and gas transport properties ( D, P, S and α) were improved with the decrease in powder particle size and the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The increase of the magnetic powder addition and a decrease of its granulation improved also mechanical and rheological parameters of the tested membranes. This improvement also had a positive effect on their gas separation properties and their potential usage in the future. [ABSTRACT FROM AUTHOR]

• Slump-flow parameters (slump and spread) of fine- and coarse-sediment suspensions are measured using a mini-slump cone. • Effects of fine- and coarse-sediment fractions on the slump-flow parameters are analyzed and empirically formulated by power-law and exponential relations, respectively. • The single- and double-layer models of Roussel and Coussot [22] and Pierre et al. [21], respectively are generalized for a conical-shaped mould in the range of 0 < α ≤ 1. • The dimensionless slump and spread of fine- and coarse-sediment suspensions are strongly correlated and their empirical relation was compared to the theoretical relations. • The slump-flow parameters and Bingham yield stress exhibit good correlations in both theoretical and empirical analyses, indicating that the slump-flow test may be used to indirectly evaluate the rheology of sediment suspensions. Slump-flow tests on concentrated fine-sediment suspensions (mixtures of clay-silt-water) and coarse-sediment suspensions (mixtures of coarse sediments and a specified fine-sediment suspension) were performed to investigate the effects of sediment fractions on the slump-flow parameters (slump and spread). The slump and spread of fine- and coarse-sediment suspensions decrease with an increase in the sediment fractions, and their empirical equations were proposed. Both experimental and theoretical results show that the slump and spread of sediment suspensions are strongly correlated. Theoretical relations of the Bingham yield stress and slump-flow parameters were also presented for comparison. The slump-flow parameters exhibit a strong correlation with the rheological parameters measured using a conventional rheometer, indicating that the rheological parameters of the tested sample could be indirectly evaluated by a simple slump-flow test. [Display omitted] [ABSTRACT FROM AUTHOR]

The synthesis of magnetic hybrid inorganic-organic membranes consisting of EC and PPO as polymer matrices and various magnetic powder microparticles was successfully performed. The results showed that the separation (coefficient α ) and gas transport properties (coefficient's P , D , S ) of the magnetic hybrid membranes were enhanced with the increase of magnetic powder addition and decrease in powder particle size. The increase of the magnetic powder addition, decrease of its granulation and selection of appropriate type of polymer matrix improved mechanical ( R 0,2 , R , R m and E ) and rheological parameters ( G′ , G′′ , and tan δ ) of the tested membranes. The hybrid membrane's resistance to elastic deformation increased with the rise of magnetic powder content, while their resistance to viscous flow decreased. The obtained magnetic membranes are characterized by not only enhanced gas transport properties (the increase in not only permeability but also in selectivity) that allow better air separation, but also improved mechanical properties. That is extremely important in the separation processes of gas mixtures at high pressures. [ABSTRACT FROM AUTHOR]

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In this study, the effect of cement gypsum type on properties of the properties of cement paste, mortar and concrete mixtures containing high range water reducing admixture (HRWR) was investigated. Two different types of cement prepared from the same clinker but containing either calcium sulfate hemihydrate or dihydrate as retarder were used. The fresh and hardened (compressive strength and drying-shrinkage) properties as well as static and dynamic rheological behavior of the mixtures were investigated. Compared to the mixtures containing dihydtate, the fresh and rheological properties of mixtures were negatively affected when cement-containing hemihydrate was used. However, hemihydrate utilization had a positive influence on the early compressive strength. The adverse effects on fresh properties were more significant in paste mixtures. These negative effects decreased in the mortar and concrete mixtures. The presence of hemihydrate in cement was found to increase the drying-shrinkage. [ABSTRACT FROM AUTHOR]

During horizontal directional drilling (HDD), the drilling fluid pressure must not surpass the maximum allowable pressure to minimize the risk of hydraulic fracturing; hence, a plan pressure can be used to manage the drilling fluid pressure. This paper addresses the prediction of plan annular pressure using the power law flow model. The annular pressures were predicted using the power law model with rheological parameters determined from a six-speed viscometer with varying shear rate ranges from 3 to 600 RPM for two HDD projects, and the predicted pressures were compared with the measurements. The results indicated that the annular pressure could be properly predicted, and the best prediction was achieved by the shear rate range of 6-100 RPM due to embracing the real shear rate of drilling fluid inside the annulus; this shear rate range is close to the recommendation (3-100 RPM) by American Petroleum Institute Recommended Practice. [ABSTRACT FROM AUTHOR]

The GlutoPeak consists in high speed mixing of a small amount of wheat flour (<10 g) added with water, and in registering a torque vs. time curve in a very short time (<10 min). Peak torque, peak maximum time, and energy values are calculated from the curve, and used to estimate the aggregation behavior of gluten. The information brought by the GlutoPeak indices is still difficult to interpret correctly, also in relation to the conventional approaches in the field of cereal science. A multivariate approach was used to investigate the correlations existing between the GlutoPeak indices and the conventional rheological parameters. 120 wheat flours-different for protein, dough stability, extensibility, tenacity, and strength, and end-uses – were analyzed using the GlutoPeak and conventional instrumentation. The parameters were subjected to a data exploration step through Principal Component Analysis. Then, multivariate Partial Least Squares Regression (PLSR) models were developed using the GlutoPeak indices to predict the conventional parameters. The values of the squared correlation coefficients in prediction of an external test set showed that acceptable to good results (0.61 ≤ R PRED 2 ≤ 0.96) were obtained for the prediction of 18 out of the 26 conventional parameters here considered. [ABSTRACT FROM AUTHOR]

A series of water-soluble ABA triblock copolymers consisting of a polyethylene glycol central block joined to two blocks of six different homopolymers have been synthesized via simple solvent-free and ecofriendly routes and characterized by FTIR and1HNMR spectroscopy. Dispersing and slump-retaining abilities of the copolymers in cement slurries were evaluated by mini-slump spread method. Rheological measurements of samples with the best performance were carried out using a rate-controlled coaxial cylinder viscometer. The test results indicate that the dispersing power of the copolymers in cement pastes is strongly affected by the structure and degree of polymerization of the monomers. [ABSTRACT FROM PUBLISHER]

The aim of the study was to determine the rheological properties of solutions of two types of sodium alginate in water. Rheological studies were carried out to determine the rheological properties of the spinning solutions. Polymer solutions of different concentrations were obtained. Based on the preliminary research of the concentrations of solutions, the proper n and k parameters were selected in order to obtain fibre by wet spinning from solution method. For selected concentrations of polymer solutions, the calcium alginate fibres were obtained. [ABSTRACT FROM AUTHOR]

We propose simple formulas for calibration of rheological parameters of Bingham fluid using a co-axial cylinder rheometer, in which the inner cylinder rotates at a constant speed, and the outer cylinder is stationary. A critical rotational speed exists due to existence of yield stress. If rotation speed exceeds the critical value, all fluid is fully sheared between the concentric cylinders. Plug flow exists only when rotation speed is less than the critical value. The effects of radius ratio and Bingham number are discussed. The rheometer with radius ratio very close to unity is discussed as a limiting case, and the result confirms previous research. Formulas for calibration are derived using Least Squares and perturbation methods for all values of radius ratio, based on measured rotation speed and torque. Two sets of experimental data are used for verification. The validation shows that the formulas derived here yield reasonable and accurate estimates of rheological parameters. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the effect of changing the concentrations of chitosan on the rheological properties of the obtained formulation. Hydrogels were prepared with 1% hydrocortisone containing 4% sodium carboxymethylcellulose with the addition of chitosan, propylene glycol- 1,2 or polyethylene glycol 400 and glycerol or paraffin. The concentration of chitosan and excipients affects the rheological properties of gels and the pharmaceutical availability of hydrocortisone. Increasing the concentration of chitosan have influence on increasing the viscosity, hardness, and cohesiveness of the tested gels. [ABSTRACT FROM AUTHOR]

Abstract: We examine the scale invariants in the preparation of highly concentrated w/o emulsions at different scales and in varying conditions. The emulsions are characterized using rheological parameters, owing to their highly elastic behavior. We first construct and validate empirical models to describe the rheological properties. These models yield a reasonable prediction of experimental data. We then build an empirical scale-up model, to predict the preparation and composition conditions that have to be kept constant at each scale to prepare the same emulsion. For this purpose, three preparation scales with geometric similarity are used. The parameter ND α , as a function of the stirring rate N, the scale (D, impeller diameter) and the exponent α (calculated empirically from the regression of all the experiments in the three scales), is defined as the scale invariant that needs to be optimized, once the dispersed phase of the emulsion, the surfactant concentration, and the dispersed phase addition time are set. As far as we know, no other study has obtained a scale invariant factor ND α for the preparation of highly concentrated emulsions prepared at three different scales, which covers all three scales, different addition times and surfactant concentrations. The power law exponent obtained seems to indicate that the scale-up criterion for this system is the power input per unit volume (P/V). [Copyright &y& Elsevier]

The aim of this work was to study the properties of methylcellulose hydrogels with supplements containing chitosan and 1% hydrocortisone. Depending on the composition of the substrate, gels are characterised by a variety of pharmaceutical availabilities. Increasing the concentration of chitosan has an influence on increasing the viscosity, hardness, and cohesiveness of the tested gels. [ABSTRACT FROM AUTHOR]