scholarly journals Rheological Characterization of Non-Newtonian Mixtures by Pressure Pipe Tests

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 419
Author(s):  
Armando Carravetta ◽  
Oreste Fecarotta ◽  
Riccardo Martino ◽  
Maria Cristina Morani
Keyword(s):  
Experimental Tests ◽  
Rheological Parameters ◽  
Rheological Characterization ◽  
Plastic Model ◽  
The Past ◽  
Pressure Pipe ◽  
Complete Set ◽  
Constitutive Parameters ◽  
Better Than

The rheological behavior of non-Newtonian fluids in turbulent conditions is an important topic in several fields of engineering. Nevertheless, this topic was not deeply investigated in the past due to the complexity of the experimental tests for the assessment of the constitutive parameters. Pressure pipe tests on Herschel-Bulkley mixtures were proven to be suitable for exploring turbulent conditions, but discrepancies with the results of tests performed in laminar flow were detected. These contradictions could be attributed to the inconsistencies of the Herschel-Bulkley model (HB) for high shear rate flows, proven by Hallbom and Klein, who suggested a more general “yield plastic” model (HK). Hence, in this study, a procedure for the estimation of the rheological parameters of both HB and HK models in pressure pipe tests is defined and rated on a complete set of experiments. The HK model performed much better than HB model in the turbulent range and slightly better than the HB model in the laminar range, confirming the consistency of the “yield plastic” model. The rheological parameters obtained by the proposed procedure were used to numerically model a dam-break propagation of a non-Newtonian fluid, showing significant differences in terms of process evolution depending on the constitutive model.

The Rheological Characterization of the Writing Performance of Carbon Black Gel Ink

2009 ◽  
Vol 66 ◽  
pp. 139-142 ◽  
Author(s):  
Ji Jun Qian ◽  
Ai Ping Chen ◽  
Zhong Xin Liu ◽  
Chun Zhong Li
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Carbon Black ◽  
Rheological Parameters ◽  
Rheological Characterization ◽  
Writing Performance ◽  
Strong Shear ◽  
The Common ◽  
The Relationship

The rheological properties of carbon black gel ink were investigated by measurement the relationship between shear stress and shear rate. The fitting to the common rheological curve of gel ink with Hersegel-Bulkley equation was introduced. And the rheological parameters used to characterize the writing properties of gel ink were proposed. The results indicated that the gel ink system possessed strong shear-thinning ability. And the writing performance of the gel ink could be characterized with rheological parameters comprehensively.

scholarly journals Contribution to the rheological study of cementitious pastes with addition of residues from the processing of ornamental rocks

2018 ◽  
Vol 11 (6) ◽  
pp. 1284-1307 ◽  
Author(s):  
V. Y. SATO ◽  
A. P. L. GALINA ◽  
J. E. S. L. TEIXEIRA
Keyword(s):  
Rheological Parameters ◽  
Cement Matrix ◽  
Rheological Characterization ◽  
Cement Pastes ◽  
Rheological Study ◽  
Mineral Addition ◽  
Flow Test ◽  
Ornamental Stones ◽  
Thixotropic Fluid

Abstract Brazil is one of the world's largest producers and exporters in the field of ornamental stones. On the other hand, the production and processing of ornamental stones result in a large volume of unused material in the form of sludge, usually discarded inappropriately in sedimentation ponds or landfills. Several researches have been carried out aiming the reuse of this material in cementitious matrixes. In the field of rheology, there are still incipient national studies that use the rheological parameters obtained experimentally to determine the behavior of cement matrix based on Portland cement. Thus, the objective of this work is to characterize rheologically the behavior of cementitious pastes with and without addition of ornamental rock processing residue (RBRO) in its natural condition. Cement pastes were prepared with three a/c ratios (0.45, 0.55, 0.65) and four residue addition contents (0%, 5%, 10%, 15%) and submitted to the flow test. In tests for characterization of the residue, the RBRO presented as a material of specific fineness and mass near the cement, having low reactive activity, indicating that the residue can be used as an inert mineral addition in the cementitious matrix. In the rheological characterization tests of the pulps studied, it was observed in the flow tests that the samples behaved as a non-Newtonian, pseudoplastic and thixotropic fluid.

scholarly journals A Metabolomic Perspective on Coeliac Disease

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Antonio Calabrò ◽  
Ewa Gralka ◽  
Claudio Luchinat ◽  
Edoardo Saccenti ◽  
Leonardo Tenori
Keyword(s):  
Energy Metabolism ◽  
Coeliac Disease ◽  
Tissue Cell ◽  
Clinical Tool ◽  
The Past ◽  
Pathological Conditions ◽  
Metabolic Fingerprint ◽  
Complete Set

Metabolomics is an “omic” science that is now emerging with the purpose of elaborating a comprehensive analysis of the metabolome, which is the complete set of metabolites (i.e., small molecules intermediates) in an organism, tissue, cell, or biofluid. In the past decade, metabolomics has already proved to be useful for the characterization of several pathological conditions and offers promises as a clinical tool. A metabolomics investigation of coeliac disease (CD) revealed that a metabolic fingerprint for CD can be defined, which accounts for three different but complementary components: malabsorption, energy metabolism, and alterations in gut microflora and/or intestinal permeability. In this review, we will discuss the major advancements in metabolomics of CD, in particular with respect to the role of gut microbiome and energy metabolism.

scholarly journals Honey Adulterated with Glucose Syrup: Rheological Modeling

2021 ◽  
Vol 65 (2) ◽  
pp. 217-227
Author(s):  
Vincent O. Anidiobu
Keyword(s):  
Rheological Behaviour ◽  
High Price ◽  
High Demand ◽  
Rheological Characterization ◽  
Ambient Temperatures ◽  
Glucose Syrup ◽  
Rheological Modeling ◽  
Acceptable Measure ◽  
Better Than

Abstract Honey's reputation for its various both nutritional and medicinal benefits and pleasant taste ensures a sustained high demand for the product all over the world. However, honey supply is quite limited and seldom meets the demand, and consequently the product commands a relatively high price and is exposed to adulteration and imitation. Honey was adulterated with glucose syrup weight of 10%, 50%, 70% and 90%, and each sample was analysed. Pure honey at ambient temperatures exhibits peculiar non-Newtonian rheological behaviour. Adulteration with glucose syrup (a Newtonian fluid) drags its viscosity towards Newtonian flow behaviour. Malcolm Cross and Ostwald-de Waele Power-Law models were used to fit the rheological data, and the former fitted better than the latter. The behaviour indices in both models increased with increasing adulteration of honey with glucose syrup. Chromatographic characterizations of honey which provides an acceptable measure of honey quality corroborated the conclusions derived from the rheological characterization of this study.

An Approach to Chemorheology of a Filled SBR Compound

1999 ◽  
Vol 72 (2) ◽  
pp. 361-383 ◽  
Author(s):  
R. Ding ◽  
A. I. Leonov
Keyword(s):  
Kinetic Studies ◽  
Rheological Parameters ◽  
Cross Linking ◽  
Rheological Characterization ◽  
Degree Of Cure ◽  
Unique Possibility ◽  
Rubber Compounds ◽  
Filled Rubbers ◽  
Basic Experiments

Abstract Three steps in complex chemorheological studies are necessary for complete rheological characterization of filled rubbers during cross-linking reaction. They include: (i) kinetic studies of cross-linking reaction, (ii) rheological studies of green rubber compounds, and (iii) correlation between the rheological parameters and the degree of cure. Basic experiments in the steps (i)–(iii) and their modeling are presented in this paper on the example of a filled SBR compound with sulfur accelerated vulcanization. The approach provides a unique possibility to trace therheological properties of rubber compounds from the green to completely cured states.

scholarly journals Rheological Characterization of Isabgol Husk, Gum Katira Hydrocolloids, and Their Blends

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Vipin Kumar Sharma ◽  
Bhaskar Mazumder ◽  
Vinod Nautiyal
Keyword(s):  
Phosphate Buffer ◽  
Power Flow ◽  
Thermal Conditions ◽  
Gel Strength ◽  
Rheological Parameters ◽  
Flow Index ◽  
Distilled Water ◽  
Rheological Characterization ◽  
Dispersion Media

The rheological parameters of Isabgol husk, gum katira, and their blends were determined in different media such as distilled water, 0.1 N HCl, and phosphate buffer (pH 7.4). The blend properties of Isabgol husk and gum katira were measured for four different percentage compositions in order to understand their compatibility in dispersion form such as 00 : 100, 25 : 50, 50 : 50, 75 : 25, and 100 : 00 in the gel strength of 1 mass%. The miscibility of blends was determined by calculating Isabgol husk-gum katira interaction parameters by Krigbaum and Wall equation. Other rheological properties were analyzed by Bingham, Power, Casson, Casson chocolate, and IPC paste analysis. The study revealed that the power flow index “p” was less than “1” in all concentrations of Isabgol husk, gum katira, and their blends dispersions indicating the shear-thinning (pseudoplastic) behavior. All blends followed pseudoplastic behavior at thermal conditions as 298.15, 313.15, and 333.15°K and in dispersion media such as distilled water, 0.1 N HCl, and phosphate buffer (pH 7.4). Moreover, the study indicated the applicability of these blends in the development of drug delivery systems and in industries, for example, ice-cream, paste, nutraceutical, and so forth.

Numerical Simulations of a Centrifugal Pump With a Non-Newtonian Fluid: Influence on Performances of Different Rheological Modelling

2019 ◽  
Author(s):  
Matteo Occari ◽  
Valentina Mazzanti ◽  
Francesco Mollica ◽  
Enrico Munari ◽  
Michele Pinelli ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Newtonian Fluids ◽  
Centrifugal Pumps ◽  
Rheological Characterization ◽  
Rate Range ◽  
Shear Rates ◽  
Rheological Modelling ◽  
Pear Juice ◽  
Dynamics Simulations

Abstract Centrifugal pumps change their performance with respect to water when processing non-Newtonian fluids. Many aspects about pumping of non-Newtonian fluids remain to be clarified due to complexity of the matter and the scarcity of investigations. In addition to experimental tests, in recent years some CFD fluid dynamics simulations have been realized to analyze the performance of centrifugal pumps with non-Newtonian fluids. Knowledge of rheology is required to correctly simulate the fluid inside the pump and predict the performance. The aim of this work is to emphasize the criticalities in the simulation of centrifugal pumps with non-Newtonian fluids, since, starting from the same rheological data, can be deduced different rheological laws, however reliable, that produce different effects on the simulations. In this paper, the performances of a model pump were measured experimentally with pear juice and accompanied by the rheological characterization of the fluid. Subsequently, the pump was simulated using five different rheology laws, all fitted to the same experimental rheogram, that differ from each other in predicting viscosity out of shear rate range experimentally measured. The pump performances were affected by the different rheology implemented. The simulations showed that the shear rates developed inside the pump are much higher than those measured with the rheometer. Consequently is necessary to achieve higher shear rates in the experimental rheogram to make sure to correctly model the rheology for shear rates values typically present in the pump.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Characterization of Rh/Si multilayer structure by HREM and HAADF

1992 ◽  
Vol 50 (1) ◽  
pp. 122-123
Author(s):  
Y. Cheng ◽  
J. Liu ◽  
M.B. Stearns ◽  
D.G. Steams
Keyword(s):  
Normal Incidence ◽  
High Resolution Electron Microscopy ◽  
X Rays ◽  
Beam Direction ◽  
Cross Sectional ◽  
Optical Elements ◽  
Resolution Electron ◽  
Point To Point ◽  
Better Than

The Rh/Si multilayer (ML) thin films are promising optical elements for soft x-rays since they have a calculated normal incidence reflectivity of ∼60% at a x-ray wavelength of ∼13 nm. However, a reflectivity of only 28% has been attained to date for ML fabricated by dc magnetron sputtering. In order to determine the cause of this degraded reflectivity the microstructure of this ML was examined on cross-sectional specimens with two high-resolution electron microscopy (HREM and HAADF) techniques.Cross-sectional specimens were made from an as-prepared ML sample and from the same ML annealed at 298 °C for 1 and 100 hours. The specimens were imaged using a JEM-4000EX TEM operating at 400 kV with a point-to-point resolution of better than 0.17 nm. The specimens were viewed along Si [110] projection of the substrate, with the (001) Si surface plane parallel to the beam direction.

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