Changes In Apparent Viscosity Research Articles

Production and quality assessment of a set-style yogurt fortified with low concentrations of Thymus vulgaris L phenolic extracts

The aim of this work was to evaluate the effect of Thymus vulgaris L phenolic extracts (TVPE) on the growth of Streptococcus thermophilus and Lactobacil- lus delbrueckii subsp. bulgaricus, and the impact of their addition in small amounts (2-8%) to a set-style yogurt with regard to variations in physico- chemical, bacteria count and organoleptic properties during 21 days storage at 4°C. The phenolic components were extracted from the crushed aerial parts of the test plant by cold maceration in hydromethanolic solution (methanol: water, 80:20 v/v). The plant polyphenolic profile was determined by HPLC. The survival ability of yogurt starter cultures in the presence of TVPE was evaluated through the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The total phenolic content (TPC) was 20.2 ± 0.57 μg GAE / mg extract. The amount of flavonoid compounds was 39.83 μg EQ/mg extract. As the quantitative measurements revealed, apigenin and fisetin (8.17, 6.83, μg GAE /mg extract respectively) emerged as major phenolic compounds from thyme aerial parts. The MIC and MBC against the growth of both lactic bacteria were obtained at 60% of TVPE concentration. A significant (p< 0.01) changes in pH, trable acidity and apparent viscosity were observed in all experimental yogurts. The best scores of sensory evaluation were recorded in samples added with 2% and 4% of TVPE as well as the control. Based on collected data, 2% and 4% of TVPE can be incorporated into yogurt without risk of deterioration in physicochemical quality or inhibition of lactic bacteria.

Polymeric and non‐crosslinked acid self‐thickening agent based on hydrophobically associating water‐soluble polymer during the acid rock reaction

ABSTRACTDifferent from traditional crosslinked polymer diverting agents, a polymeric and non‐crosslinked acid self‐thickening agent (ZPAM) based on hydrophobically associating water‐soluble polymer of acrylamide (AM), [2‐(methacryloyloxy)ethyl]trimethylammonium chloride (DMC) andN,N′‐dimethyl octadecyl allyl ammonium chloride (DOAC) was synthesized. The apparent viscosity variation of ZPAM acid solutions in acid rock reaction and rheological properties of ZPAM spent acid solutions were studied. Results showed that ZPAM acid solutions demonstrated good uninterruptedly thickening ability from low apparent viscosity to high apparent viscosity during the acid rock reaction. Meanwhile, ZPAM spent acid solutions showed good shear resistance, viscoelasticity and high temperature resistance. The thickening mechanism of ZPAM acid solutions during the acid rock reaction was explained by apparent viscosity change, rheological properties of simulative ZPAM acid solutions, and ZPAM aqueous solutions with different concentrations of CaCl2. The results showed increasing calcium chloride concentration enhanced the hydrophobic association strength of the thickener solution, resulting in increasing solution viscosity, in other words, the self‐thickening agent showed excellent salt resistance and acid resistance. In addition, the change of association strength of ZPAM acid solutions during the acid rock reaction was further confirmed via environmental scanning electron micrographs and UV spectrum. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47907.

Application of Magneto-Rheological Fluids for Investigating the Effect of Skin Properties on Arterial Tonometry Measurements

Accurate, non-invasive measurements of blood pressure and its continuous monitoring are extremely important for personal health care. Arterial tonometry, a method that is used to provide a detailed image of a patient’s cardiovascular health, shows promise for being a non-invasive alternative to current blood pressure measurement methods. However, its measurement accuracy is sensitive to patient variations such as the stiffness of the skin. Thus, this project intends to investigate the effect of skin properties (i.e., stiffness) on the accuracy of tonometric blood pressure measurements. To this end, a test platform, consisting of a pulsatile system and a tunable skin stiffness apparatus (or MR apparatus), is constructed. The cam-follower pulsatile system built based on in vivo testing of human pulses is used to generate realistic pulse waveforms. The MR apparatus is able to adjust its stiffness using Magneto-Rheological (MR) fluid whose apparent viscosity changes with applied magnetic fields. Placed at the surface of the MR apparatus, a cylinder with a frictionless plunger simulates a variable applanation force or “hold-down pressure” of tonometry by adjusting the added weights atop the cylinder. Using this test setup, a series of tests were performed by varying the input magnetic field and the weights, which effectively adjusts the skin stiffness and the hold-down pressure, respectively. The vertical displacement of the plunger caused by the internal pulse pressure was measured using a laser displacement sensor. The output displacement waveforms were analyzed with the focus on the peak amplitude difference of the waveforms, which is related to the augmentation index (a surrogate measure of arterial stiffness). The results show that there exists an “optimal” plunger weight or “hold-down pressure” that provides the most distinct output pulse waveforms. The results further show that the difference in the first two peak values decreases as the skin stiffness increases, indicating that the stiffer the skin property, the less the “hold-down pressure” effects on the accuracy of the tonometry measurements.

Impact of Soaking Time at Room Temperature on the Physicochemical Properties of Maize and Potato Starch Granules

Starch‐rich foods such as cereals and tubers are the main source of energy in human diet, but are rarely consumed in their native form, requiring cooking to deem them more digestible. The soaking of starch‐rich matrices can reduce significantly energy consumption. In this work, native maize and potato starches are soaked in water (10 g/100 g water) at room temperature (20 °C) for up to 8 h, and the physicochemical changes (morphology, particle size, apparent viscosity, and crystallinity changes) are monitored for soaking times of 1, 2, 4, 6, and 8 h. Starch granules lose gradually birefringence, while the mean particle size increases by 7.0–9.0% by swelling effect. The apparent viscosity of the starch dispersion also increases about 5–7 times after 8 h of soaking. Differential scanning calorimetry shows that the enthalpy required for achieving complete gelatinization decreased by about 80–90% after the 8 h soaking treatment. Overall, the results indicated that soaking at room temperature offers an inexpensive mean for saving energy cost involved in starch gelatinization process.

Characterization of commercial magnetorheological fluids at high shear rate: influence of the gap

This paper reports the experimental tests on the behaviour of a commercial MR fluid at high shear rates and the effect of the gap. Three gaps were considered at multiple magnetic fields and shear rates. From an extended set of almost two hundred experimental flow curves, a set of parameters for the apparent viscosity are retrieved by using the Ostwald de Waele model for non-Newtonian fluids. It is possible to simplify the parameter correlation by making the following considerations: the consistency of the model depends only on the magnetic field, the flow index depends on the fluid type and the gap shows an important effect only at null or very low magnetic fields. This lead to a simple and useful model, especially in the design phase of a MR based product. During the off state, with no applied field, it is possible to use a standard viscous model. During the active state, with high magnetic field, a strong non-Newtonian nature becomes prevalent over the viscous one even at very high shear rate; the magnetic field dominates the apparent viscosity change, while the gap does not play any relevant role on the system behaviour. This simple assumption allows the designer to dimension the gap only considering the non-active state, as in standard viscous systems, and taking into account only the magnetic effect in the active state, where the gap does not change the proposed fluid model.

Effect of pectin of tansy, Tanacetum vulgare L., on feeding behaviour and food intake in mice

Rheological properties of pectins with a different chemical characteristic in a simulated gastrointestinal fluid, as well as behavioural satiety sequence and food intake in mice, were investigated. Mice treated with pectin isolated from floscules of tansy Tanacetum vulgare L. (TVF) spent less time feeding and ate less food. Apple pectin (AU701) failed to alter food intake and feeding time. Whole-gut transit time was slowed down by both pectins. The TVF pectin showed greater apparent viscosity in simulated gastric fluid (SGF) than in water or when incubated in simulated intestinal fluid (SIF). The AU701 showed no change in apparent viscosity after sequential incubation in SGF and SIF. Our data demonstrate that TVF pectin with branched structure and a low degree of methyl-esterification can form a very viscous solution and produce greater effects on feeding behaviour and food intake.

Impact of Temperature Cycling and Isothermal Storage on the Quality of Acidic and Neutral Shelf-Stable Dairy Desserts Packaged in Flexible Pouches

The aims of the present study were, first, to identify the quality changes occurring in sterilized vanilla and strawberry pudding during storage at 20 °C; second, to understand the effect of storage temperature on aging; and, third, to determine if temperature could be used as an accelerating factor for shelf life or stability studies. Shelf-stable pudding was produced industrially and packaged in flexible pouches. Different ingredients were used to produce strawberry and vanilla pudding, and the resulting pH was 4.1 and 6.5, respectively. Pudding pouches were kept for 7 days at 20 °C and stored for up to 112 days at − 18, 4, 20, and 30 °C, or cycled repeatedly between − 18 and 20 °C, 4 and 20 °C, and 30 and 20 °C with a frequency of two cycles per week. Color, pH, apparent viscosity, flow behavior, and fluorescence spectra measurements were conducted up to 112 days of storage. The most relevant indicators to monitor quality changes in vanilla pudding were η, pH, b*, and tryptophan emission spectra, and in strawberry pudding, a*, b*, and riboflavin, tryptophan, and vitamin A emission spectra. Indeed, the temperature of 30 °C was identified as the most suitable accelerating factor for accelerated aging tests regarding changes in pH, color, riboflavin, and tryptophan fluorescence spectra of pudding, while cycles of 4/20 °C and isothermal storage at 4 °C were the most appropriate tests to accelerate changes in apparent viscosity of pudding.

Rheological properties of thick kraft black liquor at high temperature with the addition of sodium aluminate

In kraft recovery systems, there is a trend toward increasing solids content of the black liquor injected to the furnace. Higher solids contributes to combustion efficiency and stable boiler operations. However, the presence of silica can adversely affect the viscosity of the mixture in such cases. Sodium aluminate, which was used as a desilicating agent during the black liquor combustion, had an excellent effect on the removal of silicon from the bamboo kraft black liquor (BKBL) to solve the problems presented by silicon. The apparent viscosities of thick BKBL with the addition of varied sodium aluminate loading were studied with a rotational rheometer. The thick BKBL behaved as a pseudo-plastic fluid that exhibited shear-thinning. However, shear-thickening appeared when the shear rate exceeded 30 s-1 at 98 °C, which would influence the flow stability of BKBL in pipelines. When the loading was 1.5 wt.%, sodium aluminate promoted the flow and droplet formation of thick BKBL by reducing its structural strength. The Ostwald-de Waele model provided an ideal fit to the apparent viscosity data. Hence, it could be used to accurately predict apparent viscosity changes in thick BKBL.

An examination of the concept of apparent skin factor in modeling injectivity of non-Newtonian polymer solutions

In a conventional reservoir simulation, analytical well models relate well block pressure, wellbore pressure, fluid mobility, and geometric factors such as wellbore radius and grid size. Basically, fluid viscosity is assumed to be Newtonian in these models. Commercial reservoir simulators using these well models often predict unrealistic well injectivity in simulation of processes involving non-Newtonian fluids such as polymer solutions. Apparent viscosity of a polymer solution is a complicated function of flow velocity, polymer properties, permeability, porosity, salinity, etc. As the distance away from an injection well increases, flow velocity decreases; meanwhile, the apparent polymer viscosity changes drastically. For shear-thinning polymers, the average flow velocity in a well block is several orders of magnitude smaller than the flow velocity near the wellbore, especially when grid size is large. Using the average flow velocity for apparent viscosity calculation leads to an underestimate of well injectivity. Thus it is crucial to consider non-Newtonian effects in simulation of injectivity of polymer solutions.UTCHEM, a general purpose chemical flooding simulator developed at the University of Texas, uses a semi-analytical polymer injectivity model based on an extension of Peaceman's well model to non-Newtonian fluids. This model corrects the apparent viscosity in well index calculation and gives a more realistic estimate of polymer injectivity. However, the model needs to be programmed and implemented in a code. It is not practical for users of commercial simulators which do not have semi-analytical polymer injectivity model. Compared with UTCHEM, CMG-STARS, the thermal and advanced processes reservoir simulator developed by Computer Modeling Group, uses an apparent skin factor to account for non-Newtonian effects of power law fluids. The apparent skin factor can be used as an input parameter to the simulator.In this study, we revisited the analytical polymer injectivity model and proposed a general form for the calculation of apparent skin factor. The apparent skin factor is estimated using polymer rheological properties, grid size, wellbore radius, etc., and can apply to any polymer rheology. Simulation studies of polymer flooding cases were conducted to verify the concept of apparent skin factor. The results show that for shear-thinning polymers, the apparent skin factor can be estimated properly and correct the analytical well model to give close predictions compared to the semi-analytical polymer injectivity model and fine-grid simulation. The concept of apparent skin factor was proved to be useful for improving the accuracy of well injectivity calculations by commercial simulators. However, it is also worth pointing out that the apparent skin factor cannot be used for polymers which show shear-thickening behavior at high shear rates for cases of heterogeneous reservoir.

Effect of different fat replacers on the physicochemical and instrumental analysis of low-fat cupuassu goat milk yogurts.

The aim of this Research Communication was to investigate the changes in physicochemical, colour, apparent viscosity and texture properties in low-fat goat milk yogurts prepared with cupuassu pulp by the addition of inulin (SI), maltodextrin (SM), whey protein (SW) and skim milk powder (SP). Three batches of each cupuassu goat milk yogurt were prepared and analysed on the 1st day of storage by pH, proximate composition, colour, apparent viscosity, and texture. In comparison to yogurts from whole (W) or skimmed milk (S), all of the fat replacers improved the physicochemical properties (P < 0·05). The addition of the carbohydrates (inulin and maltodextrin) and proteins (whey protein and skim milk powder) also influenced the colour of the low-fat cupuassu goat milk yogurt (P < 0·05). All fat replacer treatments (SI, SM, SW and SP) presented a higher (P < 0·05) apparent viscosity than W and S yogurts. However, only the addition of skim milk powder increased the texture parameters (firmness and consistency) (P < 0·05). These results suggest that skim milk powder can be used to improve the texture properties of low-fat cupuassu goat milk. Furthermore, inulin, maltodextrin, and whey protein can potentially be applied in the goat dairy industry to increase the viscosity of yogurts.

Time and surfactant types dependent model of foams based on the Herschel–Bulkley model

Due to the special topological structure of foams changing with time, the instantaneously rheological properties of foams was difficult to study. Then an online measurement was designed to explore the relation of drainage time and rheological behavior. Foams evolution and drainage process from generation to demise were firstly investigated by SiGe300 image analysis system and electronic scale at atmospheric pressure, respectively. The evolving images of foams show that the polyhedron foams begin to appear at almost 200s, however, the sphere (or ellipsoid) foams almost become polyhedron at 550–600s. The drainage rate is divided into three stages: increasing stage, dropping stage and stabilizing stage. Meanwhile, the superficial velocity associating with gas and liquid for dropping stage is calculated, it indicates that gas phase will be beneficial to liquid-hold. A modified rheological model is theoretically proposed that combines with Herschel–Bulkley model, structural damage coefficient and foam index (m). In addition, the foam index is decided by surfactant types and concentration rather than shear rate and drainage time; structural damage coefficient is related to the initial expansion ratio and instantaneously mean expansion ratio. The continuously apparent viscosity of AFFF (3%) at any shear rates and drainage time can be obtained with instantaneously mean expansion ratio less than 48× (48 times). Finally, modified model was imported into the commercial software ANSYS Fluent-15.0 to build material properties of foams. It shows that the distribution of apparent viscosity changes with instantaneously mean expansion ratio.

Deoxygenation Reduces Sickle Cell Blood Flow at Arterial Oxygen Tension

The majority of morbidity and mortality in sickle cell disease is caused by vaso-occlusion: circulatory obstruction leading to tissue ischemia and infarction. The consequences of vaso-occlusion are seen clinically throughout the vascular tree, from the relatively high-oxygen and high-velocity cerebral arteries to the relatively low-oxygen and low-velocity postcapillary venules. Prevailing models of vaso-occlusion propose mechanisms that are relevant only to regions of low oxygen and low velocity, leaving a wide gap in our understanding of the most important pathologic process in sickle cell disease. Progress toward understanding vaso-occlusion is further challenged by the complexity of the multiple processes thought to be involved, including, but not limited to 1) deoxygenation-dependent hemoglobin polymerization leading to impaired rheology, 2) endothelial and leukocyte activation, and 3) altered cellular adhesion. Here, we chose to focus exclusively on deoxygenation-dependent rheologic processes in an effort to quantify their contribution independent of the other processes that are likely involved in vivo. We take advantage of an experimental system that, to our knowledge, uniquely enables the study of pressure-driven blood flow in physiologic-sized tubes at physiologic hematocrit under controlled oxygenation conditions, while excluding the effects of endothelium, leukocyte activation, adhesion, inflammation, and coagulation. We find that deoxygenation-dependent rheologic processes are sufficient to increase apparent viscosity significantly, slowing blood flow velocity at arterial oxygen tension even without additional contributions from inflammation, adhesion, and endothelial and leukocyte activation. We quantify the changes in apparent viscosity and define a set of functional regimes of sickle cell blood flow personalized for each patient that may be important in further dissecting mechanisms of in vivo vaso-occlusion as well as in assessing risk of patient complications, response to transfusion, and the optimization of experimental therapies in development.

Rheology evolution and CFD modeling of lignocellulose biomass during extremely high solids content pretreatment

Design of industrial scale pretreatment reactors requires the accurate physical and rheological parameters of lignocellulose biomass. Rheological properties of raw and pretreated lignocellulose materials had been characterized in previous studies. A large gap of rheological properties between the raw and pretreated lignocellulose raised a difficulty for designing proper pretreatment reactors with maximum efficiency and minimum power consumption. In this study, the dilute acid pretreatment was operated in a 20-L reactor equipped with helical ribbon impeller agitation at high solids content up to 70% (w/w) dry solids. The operation was stopped at different time points, and then the completely or incompletely pretreated lignocellulose materials were released and sent for rheological property measurement. The changing rheological properties of lignocellulose materials were recorded into an evolution profile. The apparent viscosity change was found to be closely related to pretreatment temperature, and then affected the consequent enzymatic hydrolysis yield. The dynamic rheological parameters were fitted into power law model and the CFD model was established for high solids content pretreatment and used for industrial reactor design. Furthermore, the apparent viscosity of the raw and pretreated corn stover and wheat straw increased, instead of decreased, raising an instinct difference with the system of rigid solid particles and water. The study provided the first insight into the evolution of rheological properties during the high solids content pretreatment and the basis for industrial scale pretreatment reactor design.

Properties of beta-lactoglobulin/alginate mixtures as a function of component ratio, pH and applied shear

The objective of this research was to establish effects of selected process parameters (component ratio, pH, shear) on the properties of alginate (Alg)/beta lactoglobulin (βlg) mixtures. Effects were assessed by measuring apparent viscosity, particle size, ζ-potential, hydrophobicity and conformational changes (FTIR). Intrinsic viscosity and critical concentrations were also investigated. Intrinsic viscosity of individual Alg and βlg solutions increased with pH. Shearing of Alg/βlg mixtures resulted in greater apparent viscosity at pH3 which declined proportional to increase in pH. Particle size and surface hydrophobicity were higher at pH3 and directly related to Alg concentration. Shear induced changes were observed in the secondary structure of βlg in the βlg/Alg mixtures associated with β-sheet conformations shifting from 1635.64 to 1633.71/cm and occurred only at pH5. Under certain conditions, application of shear could manipulate and create different structures from these two biopolymers.

Proposal of a multiple ER microactuator system using an alternating pressure source

This paper proposes and develops a multiple ER microactuator system using an alternating pressure source for in-pipe working micromachines, medical microrobots, and so on. A hydraulic microactuator is known to have high power density but also has the drawback of requiring large piping space for the supply and return of the working fluid. In this study, an alternating pressure system with synchronized control valves and a single pipe was proposed. As the control valves, simple ER microvalves were employed. The ER microvalves control an electro-rheological fluid (ERF) flow through its apparent viscosity change due to the applied electric field. In addition, a pressure transmitter is inserted between the pressure source and the ER valves, and low viscosity fluid such as water is used to transmit the alternating pressure. The use of the low viscosity fluid can reduce the diameter of the connecting pipe due to the low pressure loss. The proposed set-up is composed of multiple ER microactuators and an alternating pressure source; each ER microactuator consists of a pressure transmitter, two ER microvalves and a hydraulic microactuator. As the proposed system has half the number of pipes, of smaller diameter, compared with conventional hydraulic microactuator systems, it is suitable for a multiple actuator system. In this study, for verification of the working principle of the proposed system, we fabricated a large model of the system which consists of an ER finger 13mm×10mm×33mm in size as a kind of ER microactuator and an alternating pressure source using a voice coil motor. Through experiments, we confirmed the tip displacement of 17mm for the 16mm-long movable part of the finger. Then, we fabricated a gripper using two ER fingers and confirmed its independent motion.

English

Synergistic effects of additive amount, reaction time and temperature of transglutaminase on properties of WPI-NaCas composite protein films were discussed by orthogonal experiments. Results indicated that transglutaminase (TGase) modification decreased D50 and D90 of film-forming solution particles, resulting in decrease in water solubility and increase in both mechanical and water barrier properties of films under most conditions. Compared with control sample, scanning electron microscope analysis indicated that cross-section of enzyme modification sample was denser and more impermeable. However, there was no significant difference in both thermogravimetric analysis and solution apparent viscosity changes for all samples. Orthogonal experiment results also showed that TGase reaction time was the most effective factor on tensile strength&nbsp; (TS) &nbsp;and water vapor permeability (WVP) properties of film, and the secondary, tertiary factors were reaction temperature, TGase additive amount respectively. Films modified by 0.1 mg/ml TGase at 50&deg;C for 30 min exhibited the optimum mechanical and water barrier performance. &nbsp; Key words: Transglutaminase (TGase), mechanical properties, water vapor permeability (WVP), scanning electron microscopy analysis.

SDA 방법으로 제조한 오일샌드 역청의 말텐에 대한 유변학적 거동 및 비뉴톤 특성

In this paper, the rheological behaviors and non-Newtonian characteristics of maltenes which is effected by hydrocarbon solvent type, solvent mixing ratio, temperature and shear rate was measured and compared with oil sands bitumen. Maltenes was made by SDA (solvent deasphalting) method from oil sands bitumen. Oil sands bitumen had apparent viscosities of measured at a shear rate of in the range of and showed yield stress of 0.1~0.3 Pa at the temperatures below . All the oil sands bitumen and maltenes exhibited a shear-thinning, i.e. pseudoplastic behavior and apparent viscosity of maltenes decreased with decreasing carbon numbers of hydrocarbon solvent. The change in apparent viscosity with temperature could be described by the simple Guzman-Andrade equation, and maltene viscosities were decreased as the mixing ratio of n-pentane was raised. Also, all maltenes approached to Newtonian fluid as temperature were increased. the degree of pseudoplasticity was enhanced with decreasing carbon number of solvent.

Microbiological, physicochemical and rheological properties of fermented soymilk produced with exopolysaccharide (EPS) producing lactic acid bacteria strains

Growth of Lactobacillus plantarum 70810, Lactobacillus rhamnosus 6005 and a commercial yogurt starter culture in soymilk was investigated in the present study. It was found that the fermented soymilk using L. plantarum 70810 had significantly higher viable cell counts, water holding capacity (WHC, 88.27%), apparent viscosity (1840.35 mPa s) and exopolysaccharide (EPS) amount (832.15 mg/L) than the other two starter cultures in soymilk. Direct observation of microstructure in fermented soymilk indicated that the network structures of EPS-protein could improve the texture of fermented soymilk. Considering that the beneficial effects of L. plantarum 70810 in fermented soymilk, volatile compounds in fermented soymilk were further identified. Then the growth and fermentation characteristics of L. plantarum 70810 including changes in viable cell counts, pH, titratable acidity, apparent viscosity and EPS production during storage were investigated. In comparison to original soymilk base, the concentrations of the characteristic flavor compounds for fermented soymilk using L. plantarum 70810 increased, whereas hexanal, 2-pentylfuran and 2-pentanone in relation to beany flavor of soymilk decreased. In addition, fermented soymilk using L. plantarum 70810 maintained high viable cell count (>108 cfu/mL), apparent viscosity (966.43 mPa s) and amounts of EPS (635.49 mg/mL) during storage at 4 °C for 21 days.

Research on Apparent Viscosity Behavior of Municipal Sludge

Researches about the viscous of municipal sludge can be constructive especially in its drying and transportation. The change of apparent viscosity in terms of moisture content and temperature reveals that the former is primary. The apparent viscosity increases rapidly at moisture content lower than 88% with an exponent function and It is negative correlation with moisture content above 90% but only a litter change which has nothing to do with the temperature. However, it becomes to oscillate below 87% of moisture content which is attributed to complicated activities of microbe and temperature.

Modelling the Mechanics of the Circulation: Blood Rheology and Atherosclerosis

In this work, we test the hypothesis that a redistribution of blood particles is related to predilection sites of atherosclerosis,which is characterised by the deposition of lipid material and inflammatory cells. The focal distribution of lesions, shear stress,and mass transport play an important role[1] because shear stress scales inversely with enhanced transport of species in the vessel wall. Also, because 46% of blood volume is made up of particles, blood compounds have wide-reaching effects on the coupling of blood flow to the vessel walls. Indeed, some works have shown changes in flow rate, apparent viscosity and flow patterns due to particle's shape and/or concentration[2,3,4,5,6] besides literature usually focus on microcirculation that is driven by diffusive transport and differs in many other ways to the mechanics of circulation in large vessels. Here, we present some results(Fig.1) to support the hypothesis that flow trends related to atheroma development might be more accurately described by multiphase flow models[7], which is the subject of ongoing research.[1] C.G.Caro, Arterioscler. Thromb. Vasc. Biol. (2009).[2] M.Zastawny et.al., J. Multiph. Flow (2012).[3] G.Pereira, Biophysical Journal (2013).[4] K.Sugiyama et.al., J. Comput. Mech. (2010).[5] G.Pereira. Multiscale Modelling in Medicine and Biology Conference (2012).[6] F.Thomas, M.Sc. Thesis, Imperial College London (2012).[7] B.Wachem's Group, Multiflow: http://www.multiflow.org/View Large Image | View Hi-Res Image | Download PowerPoint Slide