Evaluation and role of rheological properties in sludge management

1997 ◽  
Vol 36 (11) ◽  
pp. 1-8 ◽  
Author(s):  
Steven K. Dentel
Keyword(s):  
Rheological Properties ◽  
Initial Value ◽  
Rheological Characterization ◽  
Practical Applications ◽  
Treatment Processes ◽  
Technological Advances ◽  
Sludge Characterization ◽  
Empirical Perspective

Rheological characterization of sludges represents one of the few examples of fundamentally derivable properties that has also been successfully related to actual sludge treatment processes. In understanding the relevance and utility of sludge rheology for practical applications, an historical perspective is of some initial value, and this paper summarizes previous developments in the rheological characterization of sludges and other non-Newtonian slurries, both from a theoretical and empirical perspective. In both cases, attention is brought to subtleties that must be considered if uniform and consistent rheological descriptions are to be obtained. Causes of the complex and variable rheological properties observed in sludges are then considered, with attention brought to particular aspects of upstream processes where some influence on sludge viscosity might be exerted. Finally, some practical aspects of rheometry are described. Recent research suggests that a variety of methods for sludge characterization and process optimization can be based on rheological measurements. Examples are presented that utilize both complex and relatively simplified technologies for this purpose, and some predictions are attempted of the probable directions for future developments. Internationally, approaches have differed and, while this diverse and competitive environment favors technological advances, the paper concludes by pointing out the need for consistency in rheological methods where fundamentally based parameters or regulatory concerns may be involved.

scholarly journals Rheological Characterization of a Concentrated Phosphate Slurry

Fluids ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 178
Author(s):  
Souhail Maazioui ◽  
Abderrahim Maazouz ◽  
Fayssal Benkhaldoun ◽  
Driss Ouazar ◽  
Khalid Lamnawar
Keyword(s):  
Flow Behavior ◽  
Continuous Phase ◽  
Raw Material ◽  
Rheological Characterization ◽  
Phosphate Ore ◽  
Insoluble Particles ◽  
Experimental Protocols ◽  
Solid Liquid

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

scholarly journals A Dynamic Semi-Circular Bending Configuration for the Rheological Characterization of Asphalt Mixtures

2020 ◽  
Vol 9 (3) ◽  
pp. 150-164
Author(s):  
Marina Cauhape Casaux ◽  
Silvia Angelone ◽  
Fernando Martinez
Keyword(s):  
Rheological Properties ◽  
Phase Angle ◽  
Dynamic Modulus ◽  
Plane Surface ◽  
Poisson Ratio ◽  
Asphalt Mixtures ◽  
Rheological Characterization ◽  
State Of Stress ◽  
Dynamic Loading Conditions

Many experimental procedures have been proposed for the determination of the rheological properties of asphalt mixtures. Among them, the indirect tensile test (ITT) has gained a lot of attention because of its relative simplicity and advantages. However, a biaxial state of stress is developed into the sample and then, the Poisson ratio must be estimated or measured for the calculations of the dynamic modulus. Looking for a testing configuration with the same simplicity and advantages, this paper proposes the Semi-Circular Bending (SCB) geometry with dynamic loading conditions in order to characterize the rheological properties (dynamic modulus and phase angle) of asphalt mixtures. Samples compacted in the laboratory or cored from in-service pavements can be used. A uniaxial state of stress is developed in the lower plane surface of the sample doing negligible the influence of the Poisson ratio on the dynamic modulus calculations. A specific experimental configuration was adopted and a 2D-FEM model has been used for the development of an equation for the calculation of the dynamic modulus. Two different asphalt mixtures were tested at diverse testing temperatures and loading frequencies. The obtained results have been analyzed and compared with those acquired with the more conventional testing configuration in uniaxial compression. An excellent agreement has been found for either the dynamic modulus or the phase angle with both sets of results. It could be concluded that the SCB configuration has been validated as a simple and promising methodology for the characterization of the viscoelastic response of asphalt mixtures.

scholarly journals Rheological Characterization of the Influence of Pomegranate Peel Extract Addition and Concentration in Chitosan and Gelatin Coatings

2021 ◽  
Vol 2 (3) ◽  
pp. 648-660
Author(s):  
Mirella Romanelli Vicente Bertolo ◽  
Rafael Leme ◽  
Virginia da Conceição Amaro Martins ◽  
Ana Maria de Guzzi Plepis ◽  
Stanislau Bogusz Junior
Keyword(s):  
Rheological Properties ◽  
Angular Frequency ◽  
Cross Linking ◽  
Rheological Characterization ◽  
Pomegranate Peel ◽  
All Solutions ◽  
Polymeric Solutions ◽  
Pomegranate Peel Extract ◽  
Peel Extract

In this study, the effects of an agro-industrial residue with active properties, pomegranate peel extract (PPE), were evaluated on the rheological properties of potential coatings based on chitosan (C) and gelatin (G). For this, rheological properties of the polymeric solutions were investigated in relation to PPE concentration (2 or 4 mg PPE g−1 solution), and to its incorporation order into the system (in C or in CG mixture). All solutions were more viscous than elastic (G″ > G′), and the change in PPE concentration had a greater influence accentuating the viscous character of the samples in which PPE was added to the CG mixture (CGPPE2 and CGPPE4). PPE addition to the CG mixture increased the angular frequency at the moduli crossover, indicating the formation of a more resistant polymeric network. This tendency was also observed in flow results, in which PPE addition decreased the pseudoplastic behavior of the solutions, due to a greater cross-linking between the polymers and the phenolic compounds. In general, all the studied solutions showed viscosities suitable for the proposed application, and it was possible to state the importance of standardizing the addition order of the components during the preparation of a coating.

scholarly journals Adiposity in Depression or Depression in Adiposity? The Role of Immune-Inflammatory-Microbial Overlap

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 117 ◽  
Author(s):  
Oliwia Gawlik-Kotelnicka ◽  
Dominik Strzelecki
Keyword(s):  
Metabolic Disorders ◽  
Lifestyle Changes ◽  
Occurrence Rate ◽  
Alcoholic Fatty Liver ◽  
Practical Applications ◽  
Diet And Physical Activity ◽  
Immune Alterations ◽  
Antidepressant Use

Some of the most common and debilitating conditions are metabolic disorders (metabolic syndrome and non-alcoholic fatty liver disease) and depression. These conditions are also exacerbated by the fact that they often co-occur. Although the exact mechanisms underlying such relationships are poorly known, antipsychotic medication and antidepressant use, diet and physical activity, and lifestyle factors are believed to play a role; however, their high co-occurrence rate suggests a possible pathophysiological overlap. This paper reviews several possible bases for this overlap, including hypothalamic-pituitary-adrenal axis dysregulation, immune alterations with chronic inflammation, and oxidative stress. While it is entirely possible that changes in the microbiota may play a role in each of them, interventions based on the implementation of dietary and other lifestyle changes, supplementation with prebiotics or probiotics and faecal microbiota transplantation have failed to achieve conclusive results. A better characterization of the above associations may allow a more targeted approach to the treatment of both depressive and metabolic disorders. The paper also presents several practical applications for future studies.

scholarly journals Adiposity in Depression or Depression in Adiposity? the Role of Immune-Inflammatory-Microbial Overlap

2021 ◽  
Author(s):  
Oliwia Gawlik-Kotelnicka ◽  
Dominik Strzelecki
Keyword(s):  
Metabolic Disorders ◽  
Fecal Microbiota Transplantation ◽  
Fecal Microbiota ◽  
Lifestyle Changes ◽  
Occurrence Rate ◽  
Alcoholic Fatty Liver ◽  
Practical Applications ◽  
Immune Alterations

Metabolic disorders, metabolic syndrome and non-alcoholic fatty liver disease, and depression are those of the most common and debilitating disorders worldwide that often coexist further increasing mortality risks. Although the exact mechanisms underlying this association are poorly known, several hypotheses have been proposed: antipsychotic medication and antidepressants use, diet and physical activity or any other lifestyle factors. However, the high co-occurrence rate of depression and metabolic disorders suggests a possible pathophysiological overlap. In this paper I review several raised mechanisms for this overlap which are the hypothalamic-pituitary-adrenal axis dysregulation, immune alterations with chronic inflammation, as well as oxidative stress. In my view, there is one common thread running through all the aforementioned areas of pathophysiology which is microbiota alteration. So far, several possible interventions in our microbiota have been introduced into clinical practice - dietary and other lifestyle changes, supplementation with prebiotics or probiotics, fecal microbiota transplantation – but with vague indications. A better characterization of the above associations may represent a critical step at phenotyping, and a more targeted approach to the treatment of both depressive and metabolic disorders. At the end of the paper, I give several practical applications for future studies.

scholarly journals Adiposity in Depression or Depression in Adiposity? the Role of Immune-Inflammatory-Microbial Overlap

2021 ◽  
Author(s):  
Oliwia Gawlik-Kotelnicka
Keyword(s):  
Metabolic Disorders ◽  
Fecal Microbiota Transplantation ◽  
Fecal Microbiota ◽  
Lifestyle Changes ◽  
Occurrence Rate ◽  
Alcoholic Fatty Liver ◽  
Practical Applications ◽  
Immune Alterations

Metabolic disorders, metabolic syndrome and non-alcoholic fatty liver disease, and depression are those of the most common and debilitating disorders worldwide that often coexist further increasing mortality risks. Although the exact mechanisms underlying this association are poorly known, several hypotheses have been proposed: antipsychotic medication and antidepressants use, diet and physical activity or any other lifestyle factors. However, the high co-occurrence rate of depression and metabolic disorders suggests a possible pathophysiological overlap. In this paper I review several raised mechanisms for this overlap which are the hypothalamic-pituitary-adrenal axis dysregulation, immune alterations with chronic inflammation, as well as oxidative stress. In my view, there is one common thread running through all the aforementioned areas of pathophysiology which is microbiota alteration. So far, several possible interventions in our microbiota have been introduced into clinical practice - dietary and other lifestyle changes, supplementation with prebiotics or probiotics, fecal microbiota transplantation – but with vague indications. A better characterization of the above associations may represent a critical step at phenotyping, and a more targeted approach to the treatment of both depressive and metabolic disorders. At the end of the paper, I give several practical applications for future studies.

scholarly journals Viscosity and Rheological Properties of Graphene Nanopowders Nanofluids

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 979
Author(s):  
Abderrahim Bakak ◽  
Mohamed Lotfi ◽  
Rodolphe Heyd ◽  
Amine Ammar ◽  
Abdelaziz Koumina
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Dynamic Viscosity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Heat Extraction ◽  
Rheological Characterization ◽  
Shear Rates ◽  
Rheological Measurements

The dynamic viscosity and rheological properties of two different non-aqueous graphene nano-plates-based nanofluids are experimentally investigated in this paper, focusing on the effects of solid volume fraction and shear rate. For each nanofluid, four solid volume fractions have been considered ranging from 0.1% to 1%. The rheological characterization of the suspensions was performed at 20 ∘C, with shear rates ranging from 10−1s−1 to 103s−1, using a cone-plate rheometer. The Carreau–Yasuda model has been successfully applied to fit most of the rheological measurements. Although it is very common to observe an increase of the viscosity with the solid volume fraction, we still found here that the addition of nanoparticles produces lubrication effects in some cases. Such a result could be very helpful in the domain of heat extraction applications. The dependence of dynamic viscosity with graphene volume fraction was analyzed using the model of Vallejo et al.

Rheological characterization of yield stress gels formed via electrostatic heteroaggregation of metal oxide nanoparticles

Soft Matter ◽  
2017 ◽  
Vol 13 (38) ◽  
pp. 6743-6755 ◽  
Author(s):  
Javen S. Weston ◽  
Jeffrey H. Harwell ◽  
Brian P. Grady
Keyword(s):  
Metal Oxide ◽  
Rheological Properties ◽  
Yield Stress ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Rheological Characterization ◽  
Oppositely Charged

Yield stress gels are formed when oppositely charged fumed nanoparticle species are dispersed in water. The gels are stable against sedimentation, have tunable rheological properties, and exhibit very little thixotropy.

Recent Development of Computational Predicting Bioluminescent Proteins

2020 ◽  
Vol 25 (40) ◽  
pp. 4264-4273 ◽  
Author(s):  
Dan Zhang ◽  
Zheng-Xing Guan ◽  
Zi-Mei Zhang ◽  
Shi-Hao Li ◽  
Fu-Ying Dao ◽  
...  
Keyword(s):  
Machine Learning ◽  
Light Emission ◽  
Biotechnological Application ◽  
Learning Methods ◽  
Machine Learning Methods ◽  
Technological Advances ◽  
Living Organisms ◽  
Role Of Light

Bioluminescent Proteins (BLPs) are widely distributed in many living organisms that act as a key role of light emission in bioluminescence. Bioluminescence serves various functions in finding food and protecting the organisms from predators. With the routine biotechnological application of bioluminescence, it is recognized to be essential for many medical, commercial and other general technological advances. Therefore, the prediction and characterization of BLPs are significant and can help to explore more secrets about bioluminescence and promote the development of application of bioluminescence. Since the experimental methods are money and time-consuming for BLPs identification, bioinformatics tools have played important role in fast and accurate prediction of BLPs by combining their sequences information with machine learning methods. In this review, we summarized and compared the application of machine learning methods in the prediction of BLPs from different aspects. We wish that this review will provide insights and inspirations for researches on BLPs.

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