Rheological Index Research Articles

Laboratory evaluation of the properties of high-cured crumb rubber modified asphalt containing sulfur and polymer after the oxidative aging procedure

The crumb rubber modified asphalt (CRMA) prepared by terminal blend (TB) process with high interaction temperature (260 °C) and extended curing time (6 h) is called high-cured CRMA, which has the characteristics of good storage stability and easy construction. The composition of the material has an important influence on the performance of high-cured CRMA after the oxidative aging procedure. In this study, the properties of high-cured CRMA containing sulfur and styrene–butadiene–styrene (SBS) after the oxidative aging procedure were studied. All binders were aged using rolling thin film oven test and pressure aging vessel, respectively. Fluorescence microscopy tests and rheological property tests of all binders were performed. The chemical composition of all binders was monitored using Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy. Fluorescence microscope observation shows that the particles of the SBS phase are significantly reduced and their distribution becomes uniform with the increase of the sulfur content in the high-cured crumb rubber hybrid binder before aging. Besides, the SBS phase in high-cured crumb rubber hybrid binder gradually decreases and the distribution becomes more uniform after aging. 0.3% sulfur has a certain effect on the rutting resistance of high-cured crumb rubber hybrid binder before aging, while low sulfur content has little effect on the rutting resistance. Moreover, sulfur can retard the growth of carbonyl groups of high-cured crumb rubber hybrid binder, and improve the resistance to thermal oxidation in the rheological indexes of high-cured crumb rubber hybrid binder.

Assessing the Use of Blending Charts to Estimate the Allowable Reclaimed Asphalt Pavement (RAP) Binder Content for Mixes Containing RAP from Different Sources

Abstract Blending charts are used by many agencies to design mixes with high-content reclaimed asphalt pavement (RAP). They are typically used with mixes containing more than 25 % RAP to determine the performance grade of the virgin binder or to obtain the maximum allowable RAP content. The aging condition of the RAP binders extracted from RAP can vary greatly based on years of service, climatic conditions, and traffic loading. The current specifications do not consider the stiffness of the RAP in determining the cutoff RAP percentage above which blending charts should be used. According to the current specifications, mixes containing less than 15 % RAP do not require a change to their virgin binder grade regardless of the RAP source. In this paper, extracted and recovered RAP binder from two sources representing different climatic conditions is blended with two virgin binders at different proportions. The rheological properties of the virgin and RAP binders and the resulting binder blends were compared using master curves and Black diagrams, and changes in the rheological parameters such as the crossover frequency and rheological index were noted. The blending chart procedure was used to determine the maximum allowable RAP binder ratio (RAPBR) for different mixes. The results show that the 25 % limit, currently specified, appears appropriate for the not very stiff RAP binder having a performance grade of PG94-4. However, for the stiff RAP binder (PG106+2), blending charts should be used for blends containing more than 18–20 % RAPBR. It was also shown that a change to the virgin binder is required for blends with as low as 6 % RAPBR, when the stiff RAP binder was used.

Comprehensive Effect of the Time and Water-Cement Ratio on the Rheological Properties of Power-Law Cement Grouts

The rheological properties of cement grouts are significantly affected by the changes of the time and the water-cement ratio, which determine the diffusion state of grouts in rocks and soils and influence the outcome of projects. In this study, Portland cement grouts with water-cement ratios of 0.50, 0.55, 0.60, 0.65, 0.70, and 0.75 at six moments, including 0 minutes, 5 minutes, 10 minutes, 20 minutes, 30 minutes, and 60 minutes, were evaluated to figure out the comprehensive effect of the time and the water-cement ratio on the rheological properties of power-law cement grouts. The results showed that the water-cement ratio had a great influence on both the consistency coefficient and the rheological index of the power-law cement grouts. The former appeared to have a downward trend with the increase of the water-cement ratio, and the latter appeared to have an upward trend. There was a rising tendency between the time and the consistency coefficient, while the rheological index was less affected by time. The difference between its maximum and minimum values was within 5%. Combined with the perspectives of statistical theory, practical applicability, and accuracy, the exponential model was the optimal model for showing the relationship between the comprehensive effects of the time, water-cement ratio, and consistency coefficient of the power-law cement grouts. The linear model was the optimal model of the rheological index based on the comprehensive effect of time and the water-cement ratio. Based on this, a power-law rheological equation with consideration of the comprehensive effect of time and water-cement ratio was established. The research results could not only improve the rheological theory of power-law cement grouts but also provide technical support for engineering practice.

Impact of Powder Properties on the Rheological Behavior of Excipients.

With the emergence of quality by design in the pharmaceutical industry, it becomes imperative to gain a deeper mechanistic understanding of factors impacting the flow of a formulation into tableting dies. Many flow characterization techniques are present, but so far only a few have shown to mimic the die filling process successfully. One of the challenges in mimicking the die filling process is the impact of rheological powder behavior as a result of differences in flow field in the feeding frame. In the current study, the rheological behavior was investigated for a wide range of excipients with a wide range of material properties. A new parameter for rheological behavior was introduced, which is a measure for the change in dynamic cohesive index upon changes in flow field. Particle size distribution was identified as a main contributing factor to the rheological behavior of powders. The presence of fines between larger particles turned out to reduce the rheological index, which the authors explain by improved particle separation at more dynamic flow fields. This study also revealed that obtained insights on rheological behavior can be used to optimize agitator settings in a tableting machine.

Effects of a Fuel-Resistant Modifier on the High-Temperature Characteristics of Asphalt Binders

To effectively evaluate the high-temperature characteristics of a fuel-resistant modified asphalt (FRMA), five different types of asphalt were selected, and a fuel-resistant modifier (FRM) was added to the asphalt to prepare five kinds of FRMA, and the fuel resistance of the 10 above-mentioned asphalt samples was then evaluated. Moreover, the high-temperature performance of different asphalt samples was explored, the influences of the FRM on the penetration, softening point, and rheological indexes of the different asphalt samples were analyzed. A Pearson correlation analysis was conducted on the different high-temperature indexes. Based on the results, compared with the original asphalt, the fuel resistance of the FRMA was improved by about 22% on average; the FRM was able to reduce the penetration, phase angle, and non-recoverable creep compliance of the asphalt; increase the softening point, complex modulus, rutting factors, and creep recovery; and effectively improve the high-temperature performance of the asphalt. However, as the temperature increased, the effect of the FRM on the improvement of the high-temperature performance of the asphalt declined. In addition, compared with the base asphalt, the FRM exerted a more significant effect on the rheological properties of the modified asphalt. According to the Pearson correlation analysis of the high-temperature indexes, apart from penetration, the softening point and rheological indexes featured excellent accuracy and applicability in the evaluation of the high-temperature performance of FRMAs.

Effect of Whole-Body Cryotherapy on Morphological, Rheological and Biochemical Indices of Blood in People with Multiple Sclerosis.

The aim of this study was to examine and assess the impact of a series of 20 whole-body cryotherapy (WBC) treatments on the biochemical and rheological indices of blood in people with multiple sclerosis. In this prospective controlled study, the experimental group consisted of 15 women aged 34–55 (mean age, 41.53 ± 6.98 years) with diagnosed multiple sclerosis who underwent a series of whole-body cryotherapy treatments. The first control group consisted of 20 women with diagnosed multiple sclerosis. This group had no intervention in the form of whole-body cryotherapy. The second control group consisted of 15 women aged 30–49 years (mean age, 38.47 ± 6.0 years) without neurological diseases and other chronic diseases who also underwent the whole-body cryotherapy treatment. For the analysis of the blood indices, venous blood was taken twice (first, on the day of initiation of whole-body cryotherapy treatments and, second, after a series of 20 cryotherapy treatments). The blood counts were determined using an ABX MICROS 60 hematological analyzer (USA). The LORCA analyzer (Laser–Optical Rotational Cell Analyzer, RR Mechatronics, the Netherlands) was used to study the aggregation and deformability of erythrocytes. The total protein serum measurement was performed using a Cobas 6000 analyzer, Roche and a Proteinogram-Minicap Sebia analyzer. Fibrinogen determinations were made using a Bio-Ksel, Chrom-7 camera. Statistically significant differences and changes after WBC in the levels of red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), elongation index, total extend of aggregation (AMP), and proteins (including fibrinogen) were observed. However, there was no significant effect of a series of 20 WBC treatments on changes in blood counts, rheology, and biochemistry in women with multiple sclerosis. Our results show that the use of WBC has a positive effect on the rheological properties of the blood of healthy women.

Applicability of Diffusive model for mud-flows: An unsteady analysis

Simplified versions of the Shallow Water Equations, known as Kinematic and Diffusive models, are commonly applied to the analysis of debris- and mud- flow dynamics. For this reason, the study of their applicability conditions represents an important concern. The present work investigates on the applicability conditions of the Diffusive Wave Model (DWM) for the prediction of mud-flows of shear-thinning fluid represented by a power-law rheology. The study has been carried out through the numerical solution of the DWM and the Full Wave Model (FWM) in unsteady conditions with hydrographs of different durations assigned at the channel inlet. The analysis has considered different rheological indexes, several values of the Froude (F) and of the Kinematic Wave (K) numbers. Predictions of DWM and FDM have been compared considering the mean value of dimensionless errors on maximum flow depth,εh*, and maximum discharge εq*. Positive (negative) error leads to an overestimation (underestimation) of the maximum flow depth and flow discharge in the prediction of the DWM. In the present analysis the DWM is considered safely applicable in case of underestimation, i.e. for positive values of εh* and εq*. Negative errors are acceptable if their absolute value is smaller than 5%. For all the investigated values of the governing parameters, the performance of the DWM has been found to strongly depend on the value of the rheological index, worsening as the fluid rheology becomes more shear-thinning. Regardless of the hydrograph duration, and for fixed power-law exponent (n) and F values, results indicate the existence of limiting values of the kinematic wave numberK-h and K-q above which the DWM is applicable in terms of maximum depth and discharge, respectively. For K values smaller than K-h and K-q, the DWM applicability depends also on the hydrograph duration. In these conditions and for several values of the (F, n) pair, the threshold values of the hydrograph duration necessary for DWM applicability have been identified. The presented applicability criteria represent a useful guideline for the practical application of the DWM in assessing the hazard of a mud flood.

Relationship between Rheological Indices and Cracking Performance of Virgin, Recycled, and Rejuvenated Asphalt Binders and Mixtures

Long-term cracking performance of asphalt mixtures is heavily influenced by asphalt binder rheology, and changes in binder stiffness, ductility, and aging condition significantly affect the cracking resistance of the corresponding asphalt mixture. This study evaluated the effectiveness of several common and recently developed binder rheological indices in capturing the effects of binder performance grade (PG) and source, recycled binder content, recycling agent (rejuvenator) dose, and long-term aging. These binder rheological indices included the Superpave intermediate-temperature PG (PGI), the Glover-Rowe (G-R) parameter, the crossover temperature (Tδ = 45°), the rheological index (R-value), and ΔTc. This study also directly compared the binder rheological indices with the cracking performance of corresponding asphalt mixtures to explore possible correlations and their robustness. Asphalt mixture cracking performance was evaluated using the Illinois Flexibility Index Test (I-FIT) for intermediate-temperature cracking, and the disk-shaped compact tension (DCT) test and the uniaxial thermal stress and strain test (UTSST) for low-temperature cracking. Results indicated that all the binder rheological indices (except PGI) consistently captured the effects of binder blend composition and proportions and aging condition, with a few exceptions. Results also showed that the G-R parameter, the crossover temperature (Tδ = 45°), and ΔTc had the best correlation to asphalt mixture and field core cracking performance as compared with other rheological indices (PGI and R-value), with ΔTc demonstrating the overall best correlation to mixture cracking performance.

Dynamic Modulus Characteristics of Mixtures Containing Recycled Asphalt Pavements, Warm Mix Additives, and Antistrip Agents

Abstract The utilization of reclaimed asphalt pavement (RAP) has proven to be a promising technology to solve some of the environmental issues and resource shortages in many parts of the world. The objective of this study was to investigate dynamic modulus and phase angle of surface type mixtures using two warm mix asphalt (WMA) technologies (i.e., warm mix additive E and foaming), and two liquid antistripping agents (ASAs). A total of 20 mixtures were designed and tested. Viscoelastic master curve modeling, statistical analysis, as well as continuous relaxation spectrums were conducted to obtain a better understanding of the properties of the mixtures. The results implied that RAP or WMA technologies had significant effects on mechanical performances, which should be carefully considered during mix design, but ASA agents, statistically, did not have such effects. In addition, the influence of RAP depended on WMA technology type, and the effects of ASA agents relied on aggregate and RAP source. The rheological index showed that both WMA technologies and ASA materials had negative impacts on the rheological properties of the mixtures, but the addition of RAP mitigates this impact only for mixtures containing ASA additives. Furthermore, the continuous relaxation spectrum confirmed the negative influences of WMA technologies and no obvious effects of ASA materials.

Effect of rejuvenator type and dosage on rheological properties of short-term aged binders

Using reclaimed asphalt pavement (RAP) material in pavement construction is typically an environmentally friendly practice. However, the asphalt available in RAP is already oxidized and stiffened due to various environmental processes. To compensate these problems, rejuvenators can be mixed with aged binder with the aim of restoring its original properties. This study investigates the performance of aged binders blended with three different types of rejuvenators. Thin film oven test aged PG 58–28 binder was mixed with raw waste cooking oil (R1), modified waste cooking oil (R2), and Hydrolene H90T (R3) at the concentrations of 3%, 6% and 9% by the weight of the total binder. To enhance rutting resistance, styrene–butadiene–styrene was also blended with rejuvenated binders and tested. Frequency sweep testing at a wide range of temperatures and frequencies was conducted in the Dynamic Shear Rheometer, and time–temperature superposition was used to obtain parameters including Superpave, Glover-Rowe, Shenoy, Crossover frequency and Rheological index parameters. In addition, the Multi Stress Creep Recovery test was performed to gain an in-depth understanding of the rutting performance of the binders. Based on the comparative study of different rejuvenated binders, the binder rejuvenated using a chemically modified waste cooking oil seems to most be effective in improving the overall performance of the binder without compromising its rutting resistance. In addition, the relationship between different cracking parameters indicated that they are not all compatible with each other in terms of ranking binder performance. Finally, the MSCR parameter seems to more effectively capture the influence of rejuvenation and SBS addition to rejuvenated binders more than other parameters.

Fabrication, Rheological, and Compositional Characterization of Thermoresponsive Hydrogel from Cornea.

Fabricating thermoresponsive hydrogels from decellularized tissues is a trending and promising approach to develop novel biomaterials for tissue engineering and therapeutic purposes. There are differences in the characteristics of the produced hydrogels related to the source tissue as well as the decellularization and solubilization protocols used. Detailed characterization of the hydrogels will support the efforts to optimize their application as biomaterials for tissue engineering and therapeutics. Here, we describe an optimized method for fabricating an in situ thermoresponsive hydrogel from decellularized porcine cornea extracellular matrix (COMatrix), and provide a detailed characterization of its structure, thermoresponsive rheological behavior (heat-induced sol-gel transition), as well as exploring its protein composition using proteomics. COMatrix forms a transparent gel (10-min time to gelation) after in situ curing with heat, characterized by alteration in light absorbance and rheological indexes. The rheological characterization of heat-formed COMatrix gel shows similar behavior to common biomaterials utilized in tissue engineering. The fibrillar structure of COMatrix gel was observed by scanning electron microscopy showing that the density of fibers attenuates in lower concentrations. Mass spectrometry-based proteomic analysis revealed that COMatrix hydrogel is rich in proteins with known regenerative properties such as lumican, keratocan, and laminins in addition to structural collagen proteins (Data is available via ProteomeXchange with identifier PXD020606). COMatrix hydrogel is a naturally driven biomaterial with favorable biomechanical properties and protein content with potential application as a therapeutic biomaterial in ocular regeneration and tissue engineering. Impact statement Fabrication and application of decellularized porcine corneal extracellular matrix is an emerging approach for corneal tissue engineering and regeneration. There are several protocols for decellularization of porcine cornea with various efficiencies. Here, we are presenting an optimized protocol for decellularization of porcine cornea followed by fabrication of a thermoresponsive hydrogel from the decellularized cornea matrix. Moreover, the fabricated hydrogel was rheologically and compositionally characterized as crucial features to be employed for further application of this hydrogel in corneal tissue engineering and regeneration.

Impact of constituent migration on colloid structure and rheological characteristics of emulsified asphalt with self-crosslinking modifiers

As a kind of environmentally friendly and energy saving material, asphalt emulsion was increasingly applied in the infrastructure construction industry. However, emulsified asphalt tended to face the problems of cohesive and mechanical strength deficiency, even if styrene-butadiene rubber/styrene-butadiene-styrene, modification had been performed. The waterborne additives with self-crossed characteristic showed a potential advantage on application. In this study, waterborne acrylate and polyurethane were investigated to further enhance properties of emulsified asphalt, as a novel modifier. The change of chemical constituent during the emulsion-additives interaction was firstly characterized by gel permeation chromatography (GPC) test. The dynamic shear rheometer (DSR) tests were carried out to evaluate the high-temperature characteristics comprehensively, involving temperature sweep, frequency sweep, steady shear viscosity and master curve tests. The modification mechanization was discussed according to the model of constituent migration in colloid structure of modified asphalt with additive. It released that the difference of polymer networks densities in styrene-butadiene rubber modified asphalt emulsion would cause embrittlement, while the combination of styrene-butadiene-styrene with cationic acrylate would present synergy effects in the colloid structure of emulsified asphalt. Finally, statistical analyses were conducted to evaluate the correlation among different rheological indices. The test results revealed that waterborne acrylate and polyurethane presented a positive effectiveness to modify asphalt emulsion, with enhanced performances for cold binder.

Relationship of amorphous gel-microstructure-elastoviscosity properties of alkali-activated materials fresh pastes with different Ms waterglass

In-situ measurement and quantitative analysis method were applied for the elastoviscosity properties of alkali-activated fly ash-slag with different Ms waterglass in this study. Some critical effect of the microstructure and amorphous gel on the elastoviscosity properties were fully discussed, including mesh size of microstructure, formation and transformation of amorphous gel when using Microrheology analyzer, In-situ ATR FTIR, SEM-EDX, selected dissolution process, and Low-field NMR. Results indicate that the amorphous gel was main reasons on the development of microstructure and elastoviscosity properties of alkali-activated fly ash-slag. Competitive formation mechanism between N-A-S-H gel and C-(A)-S-H gel was the main reasons of rheology properties of alkali activated materials fresh pastes: high N-A-S-H gel content of particle surfaces improve the touch point of particles-particles, increasing the formation trendy of the small mesh size and resulting to the lower rheology index. But, the formation of C-(A)-S-H gel results to the decreasing of free water due to the high interlayer space and product water. It would lead to the increasing of pore structure and mesh size.

Effect of organic deicing agents on asphalt rheology and analysis of the mechanism

In this work, the effect of organic deicing agents on the asphalt rheology and the corresponding mechanism are analyzed. Four kinds of deicing agents (A3N, A2C, A2A, NaCl) are adopted in immersion corrosion of matrix and styrene–butadienestyrene (SBS) modified asphalt. The phase angle and other rheological indexes are measured to quantify the effect. The influence of organic deicing agents on the molecular structure and components of asphalt is analyzed by Fourier Transform Infrared Spectrometer (FTIR), and the change of cation concentration in each deicing agent solution is detected by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) to reveal the cation infiltration movement into asphalt microscopically. Based on Fick's law, a cation infiltration model is established and the concentration distribution function is derived to quantify the diffusion characteristics. After immersion corrosion, the phase angles of the two types of asphalt are enhanced, while the rutting factors and the fatigue factors are abated. The corroding effect of organic deicing agents is less than that of NaCl. The proportion of light and heavy components in asphalt has been changed with increases in heavy aromatic rings, long-chain cycloalkanes, oxidized sulfoxides, and carbonyl compounds in accordance with the FTIR inspection. The diffusion characteristics of the deicing agents are investigated through the established cationic penetration model. The goodness of fit of the organic deicing agents in the model is lower than that of NaCl, indicating that the penetration of the organic deicing agents’ cations in asphalt is more complex. The diffusion contrary to the concentration gradient exists.

Evaluating technological quality of cultivated Triticum species, interspecific, and intergeneric hybrids for wheat-based products and breeding programs

Wheat genotypes such as landraces, old cultivars, wheat species, intergeneric and interspecific wheat hybrids from the gene pools nowadays offer an alternative for new wheat products and breeding programs. The present study was carried out to evaluate the grain technological quality parameters in those kinds of wheat species and hybrids under rainfed and irrigated conditions. The results of the study showed that the neglected wheat species, Triticum petropavlovskyi having the highest sedimentation index (SI), swelling index of glutenin (SIG), macro sodium dodecyl sulfate (MSDS), and Zeleny sedimentation (ZSED) values (4.9 and 4.8; 4.7 and 4.4; 77.3 and 71.0 ml; 51.0 and 44.7 ml, respectively) in rainfed and irrigated conditions, and as well as the GlutoPeak aggregation energy (AGGEN), gluten rheological index (GRI), torque before maximum (AM) values under rainfed conditions (1589.2 cm2, 68.1 and 43.0 GPU, respectively) had remarkable high gluten strength. Among the species, Triticum ispahanicum had the highest MSDS, SI, AM, and GRI values in rainfed and irrigated conditions (48.3 and 39.3 ml; 3.0 and 2.6; 37.3 and 25.7 GPU; 56.5 and 37.7, respectively). Aegilotriticum, Triticum sphaerococcum, Triticum dicoccum had also strong gluten quality. Triticum aestivum cv. Köse 220/39 possessed better gluten quality than other old cultivars and a landrace. All those genotypes can be suggested for bread-making. On the other hand, Triticum compactum and Triticum monococcum with their weak gluten strength and soft endosperm texture could be used in soft biscuit wheat breeding programs.

Plasto‐elastohydrodynamic lubrication performance of greased ellipsoid contact

AbstractThe plasto‐elastohydrodynamic lubrication (PEHL) model of the greased ellipsoid contact is established and solved numerically. In doing so, the increment theory of the plastic surface is adopted to solve the residual deformation, and the fast Fourier transform (FFT) method is employed to accelerate the deformation and stress calculations. Meanwhile, the effeteness of the PEHL model is verified through the residual stress experiment and finite element method. It is found that the plastic behaviour results in a reduction in the maximum grease film pressure. Under heavy load conditions, the grease with large rheology index, large tangential modulus or high entrainment speed of the lubricant is helpful to reducing the maximum residual deformation and maximum residual stress of the greased ellipsoid contact.

The bean flour effect on the rheological properties of the dough from a wheat flour based composite mixture

Department of Food Technology, at Saratov State Vavilov Agrarian University, studied and compared the main parameters of the rheological state of the dough from whole grain wheat flour and straight white wheat flour, dough from white beans and red beans. Dough parameters from flour composite mixtures based on beans were also studied and compared with each other. It was found that the water absorption ability of flour highly correlates with dough stability time, with a force moment characterizing the minimum consistency of the dough during the starch retrograde phase and with a force moment characterizing the maximum consistency of the dough during the end of the starch retrograde phase, as well as with the total energy consumed during dough mixing. To a lesser extent, the water absorption ability of flour correlates with the time of dough development, the force moment during the liquefaction phase, and the force moment characterizing the stability of the dough during the gelatinization phase. When comparing the main rheological parameters of the dough from the studied types of flour, it was found that both the degree of grinding and the morphological characteristics of the beans used as a donor or basis for composite mixtures influence the correlation between rheological parameters. The water absorption ability correlates to a greater extent with the main rheological indices of the dough of composite mixtures based on straight white wheat flour rather than composite mixtures based on whole grain flour.

Effects of yam (Dioscorea opposita Thunb.) juice on fermentation and textural attributes of set-style skimmed yoghurt

Yam (Dioscorea opposita Thunb.) juice was used to replace water by 10% and 20% (w/w), respectively, while the diluted yam juice was used to disperse skimmed milk powder. Set-style skimmed yoghurt samples were thereby prepared using a commercial direct vat set starter at 42 °C. Assaying results indicated that yam juice had a slight impact on the contents of total proteins and total solids of yoghurt samples but could promote yoghurt fermentation and induce texture changes. Firstly, yam juice shortened fermentation time by about 1 h and caused a higher post-acidification during yoghurt storage at 4 °C. Secondly, yam juice reduced syneresis extent during the preformed yoghurt storage, led to value increases for these textural and rheological indices like hardness, adhesiveness, cohesiveness, viscosity as well as elastic/viscous moduli, and caused a finer and compact microstructure. Furthermore, yam juice also resulted in higher viable numbers for two starter microorganisms Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the stored yoghurt samples. However, replacing water with yam juice by 20% other than 10% occasionally showed a negative impact on some textural attributes of yoghurt samples. It is thus concluded that yam juice at suitable level could be used in the production of set-style yoghurt without significant negative effect on yoghurt compositions or its fermentation, when aiming to obtain a firm yoghurt texture and endow yoghurt with enhanced health benefits from the starter strains.

Numerical analysis of flow and forced convection heat transfer of non-Newtonian fluid in a pipe based on fractional constitutive model

PurposeThis paper aims to use a fractional constitutive model with a nonlocal velocity gradient for replacing the nonlinear constitutive model to characterize its complex rheological behavior, where non-linear characteristics exist, for example, the inherent viscous behavior of the crude oil. The feasibility and flexibility of the fractional model are tested via a case study of non-Newtonian fluid. The finite element method is non-Newtonian used to numerically solve both momentum equation and energy equation to describe the fluid flow and convection heat transfer process.Design/methodology/approachThis paper provides a comprehensive theoretical and numerical study of flow and heat transfer of non-Newtonian fluids in a pipe based on the fractional constitutive model. Contrary to fractional order a, the rheological property of non-Newtonian fluid changes from shear-thinning to shear-thickening with the increase of power-law index n, therefore the flow and heat transfer are hindered to some extent.FindingsThis paper discusses two dimensionless parameters on flow regime and thermal patterns, including Reynolds number (Re) and Nusselt number (Nu) in evaluating the flow rate and heat transfer rate. Analysis results show that the viscosity of the non-Newtonian fluid decreases with the rheological index (order α) increasing. While large fractional (order α) corresponds to the enhancement of heat transfer capacity.Research limitations/implicationsFirst, it is observed that the increase of the Re results in an increase of the local Nusselt number (Nul). It means the heat transfer enhancement ratio increases with Re. Meanwhile, the increasement of the Nul indicating the enhancement in the heat transfer coefficient, produces a higher speed flow of crude oil.Originality/valueThis study presents a new numerical investigation on characteristics of steady-state pipe flow and forced convection heat transfer by using a fractional constitutive model. The influences of various non-dimensional characteristic parameters of fluid on the velocity and temperature fields are analyzed in detail.

Effect of regulating qi and invigorate blood circulation method on hemorrheology in rats with acute blood stasis syndrome and its network pharmacology research

To observe the effect of regulating qi and invigorate blood circulation method on hemorrheology in rats with acute blood stasis syndrome from the perspective of modern pharmacology, and use network pharmacology to explain its mechanism. Forty male Wistar rats were randomly divided into 6 groups. Except the blank control group, the other groups were injected with adrenaline hydrochloride and ice bath to establish the acute blood stasis syndrome model. Each group were administered Xuefu Zhuyu D ecoction, Jinlingzi Powder, Taohong Siwu Decoction, and Yanhusuo Decoction, and t he blank control group and model control group were given the same volume of saline, respectively. The blood rheology indexes such as red blood cell aggregation index of rats were measured. The TCMSP and Batman database were used to search for chemical components and targets of Jinlingzi Powder, and protein interaction analysis, GO enrichment analysis and KEGG analysis were performed on the common targets. The experimental results show that, compared with the model group, the blood rheology index levels of the Yanhusuo group and Taohong Siwu Decoction group are reduced, while the blood rheology index levels of the Xuefu Zhuyu Decoction group and the Jinlingzi S an group are significantly reduced. The network pharmacology predicts that Jinlingzi Powder has 44 active ingredients and 34 drug-disease shared targets, and KEGG analyzes 61 signaling pathways. Conclusion: IN the case of blood stasis syndrome, the effect of regulating qi with invigorate blood circulation is better than that of regulating qi alone. Network pharmacologic prediction showed that TNF signaling pathway was strongly correlated with hemorheology, and its action pathway was closely related to key tar gets IL6, TNF, CASP3.