Rheological Properties of Cell-Hydrogel Composites Extruding Through Small-Diameter Tips

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Jie Cheng ◽  
Feng Lin ◽  
Haixia Liu ◽  
Yongnian Yan ◽  
Xiaohong Wang ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Power Law ◽  
Maximum Shear Stress ◽  
Small Diameter ◽  
Maximum Cell ◽  
Assembly Technology ◽  
Hydrogel Composites ◽  
Cell Extrusion ◽  
Entrance Pressure ◽  
Maximum Cell Concentration

To form 3D structures with composites of living cells and hydrogel is now becoming an attractive technology in both bioengineering and manufacturing areas. Variant processes have been presented, most of which are based on the cell composite extrusion and deposition technique. So, the design of cell extrusion nozzle turns into an important phase, and the rheological properties of cell-hydrogel composites act as a key parameter and must be well investigated. In this paper, an entrance pressure detection device and adaptor for small-diameter tips were developed. With the hypothesis of power law fluid type, the power law constant and coefficient were calculated. As derived from the experimental results, the cell-hydrogel composites (with the maximum cell concentration of 107∕ml) show no difference from hydrogel materials in rheological properties. Based on these, the manufacturability of cell-hydrogel composites was discussed. Also, the cell viability, which is another important issue in cell assembly technology, was discussed. The peak percentage (97%) was achieved at the flow rate of 0.5mm3∕s. The extruding duration and the maximum shear stress loaded on cells were considered as two influence mechanisms.

scholarly journals Rheological properties of emulsions stabilized by green banana (Musa cavendishii) pulp fitted by power law model

2009 ◽  
Vol 52 (6) ◽  
pp. 1541-1553 ◽  
Author(s):  
Dayane Rosalyn Izidoro ◽  
Agnes de Paula Scheer ◽  
Maria-Rita Sierakowsk
Keyword(s):  
Response Surface Methodology ◽  
Rheological Properties ◽  
Response Surface ◽  
Power Law ◽  
Cone Angle ◽  
Rheological Behaviour ◽  
Quadratic Model ◽  
Soy Oil ◽  
Power Law Model ◽  
Green Banana

In this work, the rheological behaviour of emulsions (mayonnaises) stabilized by green banana pulp using the response surface methodology was studied. In addition, the emulsions stability was investigated. Five formulations were developed, according to design for constrained surfaces and mixtures, with the proportion, respectively: water/soy oil/green banana pulp: F1 (0.10/0.20/0.70), F2 (0.20/0.20/0.60), F3 (0.10/0.25/0.65), F4 (0.20/0.25/0.55) and F5 (0.15/0.225/0.625) .Emulsions rheological properties were performed with a rotational Haake Rheostress 600 rheometer and a cone and plate geometry sensor (60-mm diameter, 2º cone angle), using a gap distance of 1mm. The emulsions showed pseudoplastic behaviour and were adequately described by the Power Law model. The rheological responses were influenced by the difference in green banana pulp proportions and also by the temperatures (10 and 25ºC). The formulations with high pulp content (F1 and F3) presented higher shear stress and apparent viscosity. Response surface methodology, described by the quadratic model,showed that the consistency coefficient (K) increased with the interaction between green banana pulp and soy oil concentration and the water fraction contributed to the flow behaviour index increase for all emulsions samples. Analysis of variance showed that the second-order model had not significant lack-of-fit and a significant F-value, indicating that quadratic model fitted well into the experimental data. The emulsions that presented better stability were the formulations F4 (0.20/0.25/0.55) and F5 (0.15/0.225/0.625).

scholarly journals Viscosity Estimation of a Suspension with Rigid Spheres in Circular Microchannels Using Particle Tracking Velocimetry

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 675 ◽  
Author(s):  
Kawaguchi ◽  
Fukui ◽  
Funamoto ◽  
Tanaka ◽  
Tanaka ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Power Law ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Colloidal Particles ◽  
Fluid Model ◽  
Relative Viscosity ◽  
Circular Cross Section ◽  
Rigid Spheres ◽  
Power Law Index

Suspension flows are ubiquitous in industry and nature. Therefore, it is important to understand the rheological properties of a suspension. The key to understanding the mechanism of suspension rheology is considering changes in its microstructure. It is difficult to evaluate the influence of change in the microstructure on the rheological properties affected by the macroscopic flow field for non-colloidal particles. In this study, we propose a new method to evaluate the changes in both the microstructure and rheological properties of a suspension using particle tracking velocimetry (PTV) and a power-law fluid model. Dilute suspension (0.38%) flows with fluorescent particles in a microchannel with a circular cross section were measured under low Reynolds number conditions (Re ≈ 10−4). Furthermore, the distribution of suspended particles in the radial direction was obtained from the measured images. Based on the power-law index and dependence of relative viscosity on the shear rate, we observed that the non-Newtonian properties of the suspension showed shear-thinning. This method will be useful in revealing the relationship between microstructural changes in a suspension and its rheology.

The Equation of the Limit Replacement Width of Non-Newton Fluid in Eccentric Annulus

2013 ◽  
Vol 807-809 ◽  
pp. 2616-2619
Author(s):  
Yin Qing Liu ◽  
Mei Wei Wang ◽  
Hai Qing Cui
Keyword(s):  
Numerical Solution ◽  
Rheological Properties ◽  
Power Law ◽  
Solution Method ◽  
Cement Slurry ◽  
Power Law Fluid ◽  
Two Phase ◽  
Numerical Solution Method ◽  
Eccentric Annulus ◽  
The One

The equation of the limit replacement width of the one-dimension two-phase flow of Bingham fluid replacing Power law fluid in eccentric annulus was established, the numerical solution method of the equation mentioned above was given and taking the 3 wells, such as the He 104-27 well etc for examples, the limit replacement widths of cement slurry displacing mud, whose rheological properties can be described as Bingham and Power law modles respectively, were calculated, by using the equation and the numerical solution method mentioned above, and compared with those of cement slurry displacing mud, whose rheological properties are all described as Binghanm modle.

Rheological Properties of Chocolate Drink from Cupuassu

2008 ◽  
Vol 4 (1) ◽  
Author(s):  
Suzana Caetano da Silva Lannes ◽  
Magda Leite Medeiros
Keyword(s):  
Rheological Properties ◽  
Power Law ◽  
Microcrystalline Cellulose ◽  
Flow Behavior ◽  
Chocolate Milk ◽  
Spray Dryer ◽  
Rheological Models ◽  
Bingham Plastic ◽  
Theobroma Grandiflorum ◽  
Lower Viscosity

Flow behavior of chocolate drinks from Cupuassu (Theobroma grandiflorum, Sterculiaceae) from instantised and normal formulation, and enriched with calcium, were studied. Flow behavior was described using common rheological models (Newton, Power Law, and Bingham plastic). Experimental results, obtained at 25 oC and 40oC, fitted mostly the Ostwald and Bingham models, with R2 ? 0.997. The Newtonian model has 0.886 ? R2 ? 0.991. At 25 oC, as expected, viscosity of samples was higher and pseudoplasticity increased (n values were lower than 1). The spray-dryer process lead to differences of rheology of the ``chocolate'' milk drinks. The addition of microcrystalline cellulose plus calcium leads to a lower viscosity.

scholarly journals ON THE MECHANICAL RESPONSE OF A PRESSURIZED FUNCTIONALLY-GRADED CYLINDER

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Vlado Lubarda
Keyword(s):  
Shear Stress ◽  
Power Law ◽  
Functionally Graded Material ◽  
Elastic Moduli ◽  
Mechanical Response ◽  
Maximum Shear Stress ◽  
Radial Distance ◽  
Functionally Graded ◽  
Graded Material ◽  
Radial Inhomogeneity

A pressurized functionally-graded cylinder is considered made of the material whose elastic moduli vary with the radial distance according to the power-law relation. Some peculiar features of the mechanical response are noted for an incompressible functionally-graded material with the power of radial inhomogeneity equal to two. In particular, it is shown that the maximum shear stress is constant throughout the cylinder, while the displacement changes proportional to 1/r along the radial distance. No displacement takes place at all under equal pressures applied at both boundaries.

The effect of the addition of a slip agent on the rheological properties of polyethylene: off-line and in-line measurements

2019 ◽  
Vol 39 (5) ◽  
pp. 422-431 ◽  
Author(s):  
Arkadiusz Kloziński ◽  
Paulina Jakubowska
Keyword(s):  
Rheological Properties ◽  
Power Law ◽  
Extrusion Process ◽  
Low Density Polyethylene ◽  
Rheological Parameters ◽  
Low Density ◽  
Polymer Modification ◽  
Modified Polymer ◽  
Extrusion Head ◽  
Slip Agent

Abstract The article describes an investigation into the effect of a slip agent on the rheological properties of low-density polyethylene. As a slip modifier, oleamide was used in the amounts of 0.5, 1.0, 2.0, 3.0 and 4.0 wt.%, respectively. The process of polymer modification was carried out in a twin-screw extrusion process. The effect of the slip agent on the mass flow rate index was determined. The specific plasticisation energy of the modified polymer was also assessed based on the change in the torque of a batch mixer. The assessment of the effect of the addition of oleamide on the change in the flow and viscosity curves was made using an off-line (plastometer) and an in-line (extruder rheometer) measuring technique. The rheological parameters were determined based on the Ostwald-de-Waele power law model. The operation of the plastometer was brought closer to the principles of operation of the capillary rheometer by applying variable piston loading. In in-line measurements, an extrusion head with replaceable cylindrical dies was used. Using two rheological measuring techniques made it possible to determine the low-density polyethylene viscosity variations and the values of flow power law index (n) and consistency factor (K) in a wide shear rate range.

A Comparison of Rheological Models and Experimental Data of Metallocene Linear Low Density Polyethylene Solutions as a Function of Temperature and Concentration

2016 ◽  
Vol 12 (3) ◽  
pp. 4322-4339
Author(s):  
Salah Hamza
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Low Density Polyethylene ◽  
Effect Of Temperature ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Shear Rates ◽  
Wide Range

Knowledge of rheological properties of polymer and their variation with temperature and concentration have been globally important for processing and fabrication of polymers in order to make useful products. Basheer et al. [1] investigated, experimentally, the changes in rheological properties of metallocene linear low density polyethylene (mLLDPE) solutions by using a rotational rheometer model AR-G2 with parallel plate geometry. Their work covered the temperature range from  to  and  concentration from  to . In this paper, we reconsider Basheer work to describe the rheological behavior of mLLDPE solutions and its dependence on concentration and temperature.Until now, several models have been built to describe the complex behavior of polymer fluids with varying degrees of success. In this article, Oldroyd 4-constant, Giesekus and Power law models were tested for investigating the viscosity of mLLDPE solution as a function of shear rate. Results showed that Giesekus and power law models provide the best prediction of viscosity for a wide range of shear rates at constant temperature and concentration. Therefore, Giesekus and power law models were suitable for all mLLDPE solutions while Oldroyd 4-constant model doesn't.A new proposed correlation for the viscosity of mLLDPE solutions as a function of shear rate, temperature and concentration has been suggested. The effect of temperature and concentration can be adequately described by an Arrhenius-type and exponential function respectively. The proposed correlation form was found to fit the experimental data adequately.

Rheology of pulp suspensions of bleached sugarcane bagasse: Effect of consistency and temperature

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 601-606 ◽  
Author(s):  
JORGE H. SÁNCHEZ ◽  
GERMÁN C. QUINTANA ◽  
MERY E. FAJARDO
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Stress ◽  
Sugarcane Bagasse ◽  
Power Law ◽  
Apparent Viscosity ◽  
Power Law Model ◽  
Pulp Suspensions ◽  
Concentric Cylinders ◽  
Rate Controlled

Rheological properties, such as yield stress and apparent viscosity, of pulp suspensions of bleached sugarcane bagasse were studied in a stress-shear rate controlled rheometer using concentric cylinders geometry. Results were statistically analyzed and presented as a function of the suspension consistency (0.5% ≤ Cm ≤ 4.0%) and temperature (20°C, 40°C, and 60°C). The yield stress was influenced by the consistency and temperature. The apparent viscosity was influenced only by the consistency. A power law model was fitted to the experimental results of yield stress. In flow tests, all the suspensions showed shear-thinning behavior, which was in agreement with the Carreau-Yasuda model.

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