Investigation of Non-Newtonian Fluid Behavior and Coefficient of Friction in Water Hammer Phenomena

An unstable flow of non-Newtonian fluid, with friction in a pipe is studied, describing the water hammer phenomenon. The equations of the problem are given, then solved by a numerical approach. The non-Newtonian behavior of the fluid, as well as the effect of the coefficient of friction which represents an additional mechanism of energy dissipation are investigated. The 1D and 2D problem is used simultaneously, based on the Runge-kutta method for the descritization in time, Finite differences, Characteristics for the descritization in space. The results of this article show by verifying with experience that these methods used, in addition to being simple, are also effective and give reasonable results.

Effect of Temperature and Nanoparticle Concentration on the Viscosity of Glycerine-water based SiO2 Nanofluids

Dynamic viscosity of SiO2/22nm nanofluids prepared in a glycerine-water (30:70 by volume) mixture base liquid, referred to as GW70, is measured experimentally. Nanofluids with concentrations of 0.2, 0.6, and 1.0 percent are produced, and viscosity measurements are carried out at temperatures ranging from 20 to 80 oC using a LVDV-2T model Brookfield Viscometer. The particle size and elemental composition of nanoparticles are determined using FESEM and EDX. XRD images confirm the SiO2 peaks in the crystalline structure. The rheology of nanofluids is influenced by the nanoparticle’s concentration. In the experimental temperature and concentration range, nanofluids show Newtonian behavior. The viscosity of nanofluids enhanced as particle concentration increased and reduced as temperature increased. For 1.0 percent vol. concentration at 20oC, the maximum viscosity value is achieved, and for 0.2 percent vol. concentration at 80oC, the lowest viscosity value is observed. The viscosity of the glycerine-water base fluid was also determined at 20, 40, 60, and 80 degrees Celsius. The viscosity ratio of nanofluids to the base liquid is found to be more than one for all the nanofluids. This viscosity data is useful to estimate HTC of glycerine-water-based silica nanofluids.

Study of Rheological Behavior of Olive Oil Used as Biodegradable Lubricant

In this article, based on experimental data, we obtained three dependence relations of dynamic viscosity versus temperature by polynomial and exponential fitting. The correlation coefficients have values close to unity which proves that the obtained relations accurately describe the non-Newtonian behavior of olive oil.

Encapsulation of Curcumin in Persian Gum Nanoparticles: An Assessment of Physicochemical, Sensory, and Nutritional Properties

Curcumin is the hydrophobic yellow pigment in turmeric with considerable health-promoting effects. However, its low water solubility and stability limit its application. In the current study, curcumin within Persian gum (PG) nanoparticles at 0.5%, 1%, and 1.5% PG concentrations were encapsulated. The size of the nanoparticles was in the range of 326.0–397.4 nm. Based on the TEM images of curcumin-loaded nanoparticles, all samples had a spherical shape and existed in a particular form without aggregation. Encapsulation efficiency was in the range of 86.0–94.0%. Increasing PG concentration enhanced the encapsulation efficiency of curcumin. PG nanoparticles provided good protection on curcumin against light, hydrogen peroxide, and acidic pH. The lowest stability was related to free curcumin, and the highest was related to PG nanoparticles at 1.5% concentration. Curcumin-loaded nanoparticles at 1.5% concentration were added to kefir at 1%, 2%, and 3% concentrations. No significant differences were observed between acidity, pH, apparent viscosity, and consistency index of fortified and unfortified kefir samples. All kefir samples showed non-Newtonian behavior. Feeding rats with fortified kefir samples caused a lower level of low-density lipoprotein (LDL), total cholesterol (TC), and triglycerides (TG) compared to feeding with a standard diet.

Impact of Particle Size on the Rheological Properties and Amylolysis Kinetics of Ungelatinized Cassava Flour Suspensions

The effect of particle size on enzymatic hydrolysis of cassava flour at subgelatinization temperature was investigated. A multiscale physical metrology was developed to study the evolution of different physical-biochemical parameters: rheology, granulometry, and biochemistry. In this study, four fractions of cassava flour based on the particle sizes under 75 µm (CR075), 75–125 µm (CR125), 125–250 µm (CR250), and 250–500 µm (CR500) were screened for enzymatic hydrolysis effect. The results showed that all cassava flour suspensions exhibited a shear-thinning behavior, and the viscosity increased drastically with the increase of particle size. During hydrolysis, the viscosity reduced slightly and the non-Newtonian behavior became negligible beyond 4h of the process. The particles size for CR075 and CR125 increased steadily in diameter mean. The samples of CR250 and CR500 showed more fluctuation by first decreasing, followed by increasing in particle sizes during the process. The highest hydrolysis yield was found for samples with particle size under 125 µm (89.5–90.7%), suggesting that mechanical treatment of cassava can enhance the bioconversion rate.

Rheologic Behavior of Bovine Calf Serum

Recent studies have illuminated the rheological behavior of synovial fluid and the role of protein and hyaluronan (HA). However, with respect to artificial joint replacement in standardized wear simulations, bovine serum is used as fluid test medium. Little is known about the rheological characteristics of bovine serum, which are needed for precise tribological investigations. The steady shear viscosity η of bovine calf serum is determined for protein concentrations used in standardized wear simulations depending on shear rate γ˙ and temperature T. Additionally, the density of the serum is determined for both protein concentrations. The results show shear thinning behavior of bovine calf serum with a nearly Newtonian behavior in the range of high shear rates. Within the range of high shear rates, mean viscosities of η = 0.82–0.88 mPa·s were found for protein concentrations of 20 g/L and mean viscosities of η = 0.88–0.94 mPa·s for 30 g/L, decreasing with temperature. Densities of 1.004–1.005 g/cm3 and 1.007–1.008 g/cm3 were found for 20 and 30 g/L protein concentrations, respectively.

Exploitation of blood non-Newtonian properties for ultrasonic measurement of hematocrit

New processing techniques for manipulating blood and its components at a microfluidic scale are currently implemented. As for extracorporeal circulation, the in-line evaluation and monitoring of blood properties during these microfluidic techniques is a challenging task. Here, we show that the blood hematocrit can be measured non-invasively in a sub-millimeter medical tube using the non-Newtonian behavior of blood velocity profile. This hematocrit measurement is demonstrated on human blood with a simple Doppler ultrasound system. Results show a mean measurement error of 4.6 ± 1.3%Hct for hematocrit up to 52% and for 5 s-long ultrasonic signals. The simplicity and the measurement scale of the approach make it highly valuable for measuring hematocrit in new blood separation techniques. The approach may have an impact on in-vitro blood processing in general.