Changes In Apparent Viscosity Research Articles

Application and Optimization of Rheological Mathematical Models in Preparation and Injection Process of Polymer Flooding

The impact of shear on the properties of polymer solutions is not fully accounted for in the simulation of conventional rheological models. To optimize the application of these mathematical models, the shear rheological characteristics of polyacrylamide at various concentrations were investigated under different shear rates and shear modes. The results indicate that pseudoplastic fluid polymers exhibit two distinct rheological characteristics within their "shear thinning" rate range. The critical shear rate at this threshold signifies the point at which shear stress begins to disrupt the structure of the polymer solution, resulting in a rheological curve that transitions from high to low shear rates without reverting back to a low-to-high state. The concentration of the solution has minimal effect on the critical shear rate of the polymer, which is primarily determined by the inherent properties of the polymer itself. The application of rheological models during preparation and injection processes can elucidate the effects of shear on polymers by analyzing changes in apparent viscosity. Furthermore, the rheological model following supercritical shear rates requires modifications to the consistency coefficient (K) and flow index (n) based on shear rheological data obtained from high to low shear rates.

Rheological model of cement-based material slurry with different water-cement ratio and temperature

PurposeThe purpose of this paper is to obtain a constitutive model of cement-based material in the rheological stage, which owns the different water-cement ratio (w/c) and temperature and have a significant impact on the workability of concrete materials.Design/methodology/approachIt is introduced a modified Arrhenius equation into the Herschel–Bulkley model, which is widely applied in rheological analysis and constructed an ordinary differential equation (ODE) of w/c from the Navier–Stokes equation. By solving the ODE, an approximate constitutive relation of cement-based materials included w/c and temperature is derived. Compared with the experimental results, the present model is validated.FindingsThe shear stress and shear rate curves with different w/c and temperature are simulated by the present method, and the present model can be applied to analyze the changes of apparent viscosity in cement-based material slurry as the w/c and temperature varying.Originality/valueThis work gives a mathematical model, which can effectively approximate the shear stress–shear rate relation with different w/c and temperature in the rheological stage of cement-based material.

Evaluation of sono-physico-chemical and processing effects in the mixed sarcoplasmic protein/soy protein isolate system

Since it may be employed to guide the production of high-quality plant protein as a partial substitute for animal protein using sono-physico-chemical effects, it is important to investigate the mixing of animal and plant protein in ultrasound (UID)-assisted processing systems. A study group of sono-physico-chemical processing with five distinct soy protein isolate (SPI)/ sarcoplasmic protein (SPN) ratios was developed in this work. The results showed that adding additional SPN to the mixed protein can increase its sono-physico-chemical impact, and this effect is greatest when the ratio of SPI to SPN is 1:3. The high SPN group's grafting rate rose from 39.13% to 55.26% in comparison to the high SPI content group. Quercetin (Que) may more readily modify SPN than SPI in the “dual protein” system used in this work, highlighting the critical function of plant protein in controlling the effects of UID-assisted processing in the “dual protein” system. Changes in apparent viscosity and microstructure are the primary parameters that affect the severity of sono-physico-chemical effects in SPI/SPN mixed protein systems, in addition to structural variables.

Effect of pulsed electric field on physicochemical properties of rice and black gram fermented batter

AbstractThis study aimed to investigate the effect of PEF treatment (5, 20, and 35 kV/cm) on functional, physicochemical, and microbiological properties of rice and black gram fermented batter. The PEF treatment efficaciously inhibited the total bacterial, yeast, and mold count from 1 × 107 to 1.8 × 105 CFU/gm and 3.7 × 103 to 4.1 × 102 CFU/gm, respectively at 35 kV/cm. PEF treatment significantly improved protein solubility, reducing sugar, total phenolic content, and antioxidant activity in the fermented batter. Herschel–Bulkley model best described the change in apparent viscosity which significantly decreased in PEF treated samples. Further, FTIR analysis of the PEF treated sample exhibited an increase in the area of percentage in each functional group. The results of the study suggest that the potential of PEF treatment at 20 kV/cm enhanced bioactivity and bioavailability of protein, and carbohydrate content as well as impeded the microorganisms to avoid over‐fermentation.Practical applicationsPEF technology effectively inhibits or inactivates the microorganisms in rice and black gram fermented batter and is highly suitable to avoid over‐fermentation without major changes in the physicochemical properties of batter. Therefore, this study promotes inevitable scientific information that could further investigate the industrial production of fermented rice and black gram batter with targeted physicochemical properties through PEF treatment. This also creates new opportunities for food industries to strategically diversify microbial arrest aspects in the commercial fermented batter.

Formulation and Physical Stability of High Total Solids Lentil Protein-Stabilised Emulsions for Use in Plant Protein-Based Young Child Formulae.

The demand for high-quality plant protein products is increasing and the aim of this work was to evaluate the impact of increasing the total solids content on the formation and stability of lentil protein stabilised oil-in-water emulsions. A series of emulsions were formulated using different proportions of total solids: 23, 26, 29, 32, and 35% (w/v). The emulsions were formulated using three ingredients-lentil protein, sunflower oil, and maltodextrin-which made up 15.85, 27.43, and 56.72% (w/w) of the total solids, respectively. The changes in apparent viscosity, particle size distribution, and colour during thermal processing were evaluated, with the physical stability investigated using an analytical centrifuge. The apparent viscosity of the solutions increased with total solids content (25.6 to 130 mPa.s-1), as did redness colour intensity (a* value increased from 5.82 ± 0.12 to 7.70 ± 0.09). Thermal processing resulted in greater destabilisation for higher total solids samples, as evidenced by greater changes in particle size, along with decreased redness colour. These results bring a better understanding of high total solids plant protein emulsions and factors affecting their stability, which could be used for the development of cost-effective and sustainable processing solutions in the production of plant protein young child formulae.

Modeling of the Phase Inversion Point of Crude Oil Emulsion by Characterization of Crude Oil Physical Properties.

Accurate prediction of the phase inversion point (PIP) of crude oil emulsion (COE) will give important guiding significance to the mixed transportation technology during the crude oil mining process. The influence of water cut of a system on viscosity characteristics of the COE was studied by emulsification experiments with 16 kinds of crude oils having significant differences in physical properties. The results showed that under the condition of low water cut of a system, the crude oils can emulsify all the water to form stable W/O emulsions with apparent viscosities much higher than those of pure crude oils. When the water cut of a system exceeds a certain critical value, the crude oils have no ability to emulsify all water; instead, they are wrapped by a water phase and form unstable O/W emulsions, and their apparent viscosities decrease sharply compared with those of pure crude oils. The critical water cut of a system corresponding to the abrupt change of apparent viscosity of the COE is the PIP of the COE changing from the type of W/O to O/W. Furthermore, the apparent viscosities of stable W/O emulsions decrease with increasing shear rate and temperature and meanwhile increase dramatically with the increasing water cut of a system. The apparent viscosities of unstable O/W emulsions decrease with increasing shear rate, water cut of a system, and temperature and are far lower than those of pure crude oils. Four typical parameters were chose as the representation to describe the crude oil physical properties (COPPs), that is, the content of saturates, the content of aromatics, the content of surfactants, and the crude oil acid number. On the basis of the quantitative description of COPPs, a prediction model for the PIP of the COE was established. The results of model verification showed that the mean relative deviation of prediction results was 2.9%.

Evaluation of low-gravity-solids sedimentation in non-Newtonian synthetic-based drilling fluids monitored by gamma-ray attenuation technique

ABSTRACT Drilling fluids are used in the process of drilling wellbores. They are formulated by a combination of solubles and suspended solids. During drilling, cuttings of rock formation may get in the mix. Some of them are too small and light to be removed from the fluids. They are called low-gravity solids (LGS). In no drilling situations, both solids may settle due to gravity. This project aimed to characterize the physical and rheological properties of synthetic-based drilling fluids and monitor the distribution of solids concentration in batch gravity settling experiments. The interplay of solid content and mud rheology was evaluated by pycnometry, retort, and rheological analysis. The Gamma-ray Attenuation Technique was applied to monitor the solid concentration along the test tube as a function of time. We analyzed two similar muds that slightly differed by the presence LGS The fluids presented non-Newtonian behavior, clear separation of solids in two phases and apparent viscosity changes. After 90 days, the clarified liquid region was formed between 16 and 22 cm from the bottom of the tube. This region took shape between 7 to 80 days, and the maximum solid concentration was approximately 9%. Finally, the LGS increased the fluid resistance of settling.

On-line ascertain the processing fluidity of concentrated poly(vinyl alcohol) aqueous solutions

Understanding the viscous fluid behavior of concentrated aqueous solution of poly (vinyl alcohol) (PVA), wherein macromolecular coils severely overlap and/or entangle each other, is of significance to the process design of PVA solution fabrication. However, exploiting the fluidity of PVA solutions under severe conditions of simultaneously high operational temperature (Top), high concentration (CPVA) and large polymerization degree (PD) has been less involved in the past studies irrespective of practical importance. Herein, we utilize a self-made hydrothermal kettle with a built-in online viscometer to systematically trace the changes of apparent viscosity (ηap) of PVA aqueous solutions arising from the variables of Top (up to 160 °C), CPVA (high as 28%) and PD (largest at 3000). Applying Andrade's equation, the activation free energy of viscous flow (Eη) is deduced from ln ηap ∝ 1/Top. It shows that all the values of Eη approximate to 37 (±3) kJ·mol−1 although both CPVA and PD increased progressively, indicating that these two factors will not affect the Top sensitivity of ηap. Meanwhile, the contour plots of ηap in CPVA-Top space are established for various PVAs with different PDs, to manifest the development trend of fluidity upon multiple external-fields coupling. Clarifying the synergic effect of CPVA-Top-PD on ηap may offer guidance for the preparation of PVA films by determing appropriate solution processing variables. The results of our study are of help to the PVA fabrications such as spinning fiber and casting film, in which precise control of flowability of concentrated solution is crucial.

高圧力駆動ERマイクロアクチュエータに関する研究

For power microrobots that work in narrow space such as inside of pipes of industrial plants, microactuators using ER microvalves that control ERF (electro-rheological fluid) flow due to the apparent viscosity change in electric fields (ER effect) have been investigated. Higher pressure can realize higher performance due to the decreased cross section of the hydraulic actuator and the decreased diameter of the pipes with lower flow rate for the same fluid power. However, the ER effect of liquid crystal type ERF is decreased when the shear rate exceeds the limit. Hence, in this study, we proposed and designed an ER microactuator considering the shear rate limit. Then we fabricated the ER microvalve using MEMS fabrication process. Finally, we clarified the characteristics of the ER microvalve, the rubber-tube microacuator, and the ER microactuator using the elements experimentally.

ВЛИЯНИЕ ОЛИВКОВОГО МАСЛА НА РЕОЛОГИЧЕСКИЕ ХАРАКТЕРИСТИКИ МАЙОНЕЗА

Rheological properties are an important parameter for the quality of mayonnaise. This article in-vestigated the effect of adding olive oil on the rheological properties and color change of mayon-naise. The influence of the storage time of mayonnaise in the refrigerator on the change in rheo-logical properties was also investigated. Mayonnaise was prepared on a laboratory rotary disperser of the Turrex type with a rotor / stator system with a rotor speed range (10000-30000 rpm) at room temperature. Mayonnaise contains 75% oil with varying proportions of sunflower oil and ol-ive oil. Rheological measurements were carried out on a Brookfield rotary viscometer with con-centric cylinders at temperatures of 10 ° C and 25 ° C. Based on the data obtained, the consistency coefficient of the rheological parameters, the flow index and the apparent viscosity were calculat-ed. The color of the test samples of mayonnaise was measured using a three-color colorimeter. All mayonnaise samples exhibit non-Newtonian pseudoplastic flow with a defined thixotropic loop area. Research results have shown that the addition of olive oil affects the rheological properties and color of mayonnaise. The addition of olive oil to the oil phase of mayonnaise reduces shear stress, apparent viscosity, consistency factor and color change at 25 ° C and 10 ° C. When storing mayonnaise in the refrigerator for 15 days, the rheological parameters change. Sunflower oil may-onnaise (75%) has the highest value (L), which means it is measured instrumentally as the bright-est.

Effect of the Addition of Whole and Milled Flaxseed on the Quality Characteristics of Yogurt.

The present study aimed to analyze the effect of the addition of whole and milled flaxseed on the quality characteristics of yogurt. In the first stage of the research, the optimal dose of flaxseed was determined. In the second stage of the research, it was assessed whether the selected qualities of yogurt were affected by the form of flaxseed (whole or milled) and the time of addition (before or after fermentation). The yogurts obtained were stored at 5 °C for 21 days, and the changes in active acidity, apparent viscosity, syneresis, and the number of yogurt bacteria were determined. The results of the second stage of the study were subjected to two-way analysis of variance (ANOVA) (p < 0.05). The study showed that the addition of milled flaxseed to yogurts in the amount of 1% was optimal. Time and form of flaxseed supplementation significantly influenced the changes in active acidity, apparent viscosity, and syneresis in the tested yogurts. The addition of flaxseed did not significantly change the content of yogurt bacteria. The results indicate that to achieve increased apparent viscosity and reduced syneresis, it is more advantageous to use milled flaxseed rather than whole flaxseed.

Interaction properties between molten metal and quartz by molecular dynamics simulation

The interaction properties between metal droplet and substrate play a crucial role in additive manufacturing technology based on depositing microdroplet. However, few studies have focused on the wettability and slippage between them due to the experimental observation challenge. In this work, molecular dynamics simulation is employed to investigate the effects of metal type, temperature, feature size, and driving force on contact angle and slip length and clarify their influence mechanisms. The results suggest that Ag has the smallest contact angle and slip length among Cu, Ag, and Au, and the more intense interaction between metal and quartz results in a smaller contact angle and slip length. The temperature has a weak influence on contact angle and slip length, and both of them decrease slightly with increasing temperature. The slip length rises rapidly and then trends to a constant when the feature size becomes large, which can be interpreted by the change in apparent viscosity of molten metal near the quartz. Furthermore, the slip length is proportional to the driving force, while it will reach a plateau when the driving force is considerably large. These conclusions can provide theoretical guidance and reference for continuous medium simulation.

Survival of &amp;lt;i&amp;gt;Lactobacillus acidophilus &amp;lt;/i&amp;gt;in Fruit-Flavored Greek Yogurt Acid Whey

Greek yogurt has become much more popular within the last 15 to 20 years. The by-product of Greek yogurt manufacture is acid whey. Although acid whey has been considered a waste product, researchers are exploring various uses of this whey. Since the health benefits of consuming probiotics are widely known, one may propose adding probiotics to acid whey to form a probiotic beverage. Typically, probiotic bacteria do not thrive in acidic conditions. It would be beneficial to determine if the probiotic Lactobacillus acidophilus can survive in these acidic conditions. The objectives were to determine the growth of L. acidophilus in acid whey resulting from manufacturing Greek yogurt and to study any changes in apparent viscosity, pH, and titratable acidity over 4 weeks of refrigerated storage. Plain yogurt was manufactured, and whey was separated from plain yogurt to yield Greek yogurt and acid whey. Acid whey was batch pasteurized, cooled, sweetened, flavored with pineapple flavoring, inoculated with L. acidophilus, and stored at 4°C for 4 weeks. The log L. acidophilus counts progressively decreased from 7.84 immediately after manufacture to 2.06 at week 4. There were no significant changes in pH and titratable acidity of the pineapple-flavored probiotic acid whey over 4 weeks of storage, indicating product stability over shelf life. Viscosity changed over the storage time with minimum values at week 2 and maximum values at week 4. Although the counts declined over 4 weeks of storage, some L. acidophilus survived in the pineapple-flavored acid whey.

Effect of ultrasonic treatment on rheological and emulsifying properties of sugar beet pectin.

The effects of ultrasonic treatment on rheological and emulsifying properties of sugar beet pectin were studied. Results indicated that intrinsic viscosity ([η]) and viscosity average molecular weight ([M v]) decreased with the increased time from 0 to 30 min but increased when the duration prolonged to 45 min. The change of apparent viscosity with shear rate of all pectin solutions could be well described by Sisko model (R 2 ≥ .996) and the infinite‐rate viscosity (η ∞) and the consistency coefficient (k s) values decreased after ultrasonic treatment. Ultrasonic treatment could have an effect on dynamic moduli and activation energy of sugar beet pectin solutions. Particle size of pectin emulsions decreased and absolute zeta potential increased with increased time from 0 to 20 min. Excessive ultrasonic duration (30 and 45 min) could result in the aggregation of oil droplets in pectin emulsion and decrease in emulsifying stability. It could be concluded that ultrasonic treatment could affect the rheological and emulsifying properties of sugar beet pectin. The results have important implications for understanding the ultrasonic modification of sugar beet pectin.

Increased CO2 storage capacity using CO2-foam

Reduction of the CO2 mobility is beneficial during subsurface sequestration of anthropogenic CO2 in saline aquifers and hydrocarbon reservoirs by mitigating flow instabilities leading to early gas breakthrough and poor sweep efficiency. Injection of CO2 foam is a field-proven technology for gas mobility control. Foam generation and coalescence are compared between six commercially available surfactants with a range in CO2 solubility, during unsteady state injection of dense CO2-foam in a long sandstone outcrop core (1.15 m). Foam generation categories and foam decay were defined based on the observed changes in foam apparent viscosity during generation and coalescence. The degree of CO2 solubility influenced apparent viscosity development and peak foam strength for the tested surfactants. Variations in foam peak strength resulted in a range of water saturations at CO2 breakthrough (up to 24 percentage points difference observed experimentally), with implications for the CO2 storage capacity.

Analysis of a Compact Squeeze Film Damper with Magneto Rheological Fluid

Rotor systems play vital role in many modern day machinery such as turbines, pumps, aeroengines, gyroscopes, to name a few. Due to unavoidable unbalance in the rotor systems, there are lateral and torsional vibrations. Ignoring these effects may cause the system serious damages, which sometimes lead to catastrophic failures. Vibration level in rotor systems is acceptable within a range. Focus in this work is to minimize the vibration level to the acceptable range. One of the ways vibration level can be minimised is by means of providing damping. To accomplish this task in this work a new concept squeeze film damper is made by electro discharge machining which is compact in configuration, is filled with magneto-rheological (MR) fluid and tested out on one support of a Jeffcott rotor. This compact squeeze film damper (SFD) produces damping in a compact volume of the device compared to a conventional SFD. MR fluid is a smart fluid, for which apparent viscosity changes with the application of external magnetic field. This compact damper with MR fluid provides the variable damping force, controlled by an external magnetic field. In this work, proportional controller has been used for providing the control feedback. This MR damper is seen to reduce vibrations in steady state and transient input to the Jeffcott rotor. Parametric study for important design parameters has been done with the help of the simulation model. These controlled dampers can be used for reducing vibrations under different operating conditions and also crossing critical speed.

Effect of agitation speed on freezing process of ice cream using a batch freezer

AbstractThis study investigates the effect of agitation speed on the freezing process of ice cream using a batch freezer. The temporal change in apparent viscosity during freezing is measured by the Metzner–Otto method. It was found that the apparent viscosity of ice cream after freezing decreased with an increase in the agitation speed. In addition, the number of bubbles incorporated into the ice cream also increased with the increase in the agitation speed. The bubbles were broken down into smaller bubbles by the higher shear force, that is, the higher agitation speed. Furthermore, a narrower distribution of the bubble size was obtained at higher agitation speeds. This indicated that the rheological properties and the microstructure of ice cream can be controlled by the agitation operation.Practical applicationsThis study clarified the effect of agitation speed on ice cream properties such as the apparent viscosity, the overrun and the size distribution of contained bubbles. Especially, the apparent viscosity is important for both industries and consumers. The Metzner–Otto method was used to directly measure the temporal change in the apparent viscosity during freezing. This temporal change has not been investigated so far. It was found that the apparent viscosity decreased with the increase in the agitation speed. In other words, the rheological properties can be controlled by the agitation operation. In industries, the continuous freezer is more preferable than the batch freezer used in this study. Nevertheless, the knowledge would be quite useful for the development of industrial processes of ice cream.

Short communication: Effect of stirring operations on changes in physical and rheological properties of nonfat yogurts during storage

The rheological and physical properties of stirred yogurt depend on several parameters, including the mechanical stress caused by stirring, smoothing, and cooling conditions (duration, intensity, or temperature). However, the literature reports little information about the effects of mechanical stress from all of the stirring operations on changes in yogurt properties during storage. The aim of this study was to determine, by means of a technical scale unit, the combined effects of stirring in the yogurt vat, smoothing, and cooling on changes in the rheological properties of nonfat yogurt during storage at 4°C. The yogurt was standardized to 14% total solids, 0% fat, and 4% protein, and was stirred with a technical scale unit using 2 stirring durations (5 min or 10 min), 2 types of cooling systems (plate or tubular heat exchanger), and 2 smoothing temperatures (38°C for yogurts smoothed before cooling or 20°C for yogurts smoothed after cooling). All yogurts were stored for 22 d at 4°C, and we determined the combined effect of the stirring operations on changes in syneresis, apparent viscosity, firmness, consistency, and flow time. During storage, post-acidification was the same for all stirred yogurts and involved restructuring of the protein network, which resulted in an increase in all properties except syneresis, which decreased. The combined stirring operations did not modify changes in syneresis during yogurt storage but did affect flow time, viscosity, consistency, and firmness. Changes in flow time depended on smoothing temperature, and viscosity and consistency depended on the cooling system used. Firmness was the property most affected by all combined stirring operations during storage. Therefore, the technical scale unit was effective for quantifying the combined effects of stirring, smoothing, and cooling on changes in yogurt properties during storage. This study also confirmed that the restructuring of stirred yogurt depended on the mechanical stress that occurred during the stirring process.

Laminar flow cleaning of gelatinised, partially hydrolysed starch

SummaryThe cleanability of food contact materials is, among others, determined by the physico‐chemical properties of the soiling material. In the current study, starch of different origin was gelatinised and partially hydrolysed with diastase. The degree of hydrolysis was determined as the reducing capacity in terms of dextrose equivalents, and by the changes in apparent viscosity and surface tension. After spreading the starch paste on electropolished stainless steel coupons and subsequent drying, the removal was studied with a laboratory flow cell. These cleaning tests revealed a higher cleaning effectivity for smaller dextrins, which can be attributed to corresponding changes in solubility. Furthermore, the addition of commercially available diastase to demineralised water increased the cleaning effectivity of starch and dextrin soils at 25 °C. The results indicate that smaller starch breakdown products require reduced energy for removal so that cleaning processes can be adequately adjusted.

Switch Effect, Water‐Like State, and New Interaction Mechanism of an H‐Bonded Polycation–Polyacrylamide System to Realize Instant Decolorization of Dyeing Wastewater

AbstractA switch for controlling hydrogen bonds is incorporated into a polymer‐based system of polyamine polycation and polyacrylamide, with an ultrahigh molecular weight of 18 million; a surprising process results whereby the apparent viscosity of the whole system suddenly plunges from 321 cps to below 6.5 cps, forming a new water‐like phase state (WLPS) of an H‐bonded polymer‐based system. When WLPS products are used as decolorant materials to purify dyeing wastewater, they can flow similar to water during mass transfer and be quickly dissolved, immediately interacting with the anionic dyes in water. This observation is the first of a sudden change in apparent viscosity and the formation of a water‐like state in a polymer‐based system. Moreover, due to the switch effect to control hydrogen bonds, WLPS decolorants can change from water‐like states to strong hydrogen bonding states after interacting with anionic dyes, thus increasing the attractive forces of formed flocs to realize the instantaneous and highly adaptable decolorization of dyeing wastewater. It only took 10 s for the WLPS decolorants to remove more than 95% of various dyes in dyeing wastewater. Subsequently, a series of new cohesive floc structure–forms are first discovered by a computer imaging optical microscope.