Aggregation Of Suspensions Research Articles

Research on the relationships between river erosion and sedimentation and energy loss in the Yangtze River Basin of China

River scour and siltation, inherently prolonged and multifaceted phenomena, profoundly impact the hydraulic conductivity and navigational safety of waterways, thereby rendering the precise forecasting of their fluctuations a paramount and unresolved challenge. This study embarks on a novel investigative trajectory by examining energy dissipation in rivers, specifically through the scrutiny of empirical hydrological records. Employing the principles of energy balance theory, this study elucidates the intricate connection between energy losses and sedimentation volumes in the upper reaches of the Yangtze River and at its confluence with the significant tributary, the Jialing River.Our findings diverge from conventional wisdom, revealing that standard metrics of energy loss, encompassing kinetic, potential, and total mechanical energies, along with momentum losses, inadequately characterize the complexity of sediment deposition processes. In contrast, we demonstrate that the loss of suspension power is a more indicative measure of sedimentation quantity. Through meticulous comparisons of various formulations for calculating suspension power, we identified a formula grounded in the concept of minimal available power dissipation in river systems that exhibits superior accuracy in correlating suspension power losses with sedimentation patterns in river sections. This formula's efficacy is further enhanced when considering aggregate suspension power dissipation under the influence of tributary inflows, enabling refined predictions of sedimentation variations along river segments. In conclusion, the insights derived from this meticulous research contribute significantly to the realm of river resource management and the pursuit of sustainable, high-quality aquatic ecosystem development.

Functional insights into the interaction of Lactobacillus spp. and potentially protective agents

The research addresses the critical need to explore how potentially protective agents (PPAs) influence the cellular characteristics of probiotic bacteria, with a focus on strain-specific responses. This study aimed to reveal the effect of 48-h exposure of the Lactobacillus spp. strains to selected PPAs on the viability, metabolic activity, stress response, surface properties, and physicochemical stability of bacterial suspensions. Results provide new insights into the potential risks or benefits of using the tested PPAs in probiotic production based on the analyzed strains, offering valuable information on their impacts on bacterial cells. Trehalose (TRE) and vitamin C (VC) notably impact the metabolic activity and surface characteristics of cells, with TRE improving viability and VC changing surface roughness and particle size distribution (PSD), suggesting a delicate balance between stress induction and viability enhancement. Inulin (IN) decreased metabolic changes, pointing the complex interplay between PPAs and bacterial metabolism. Results of zeta potential and PSD measurements revealed that other PPAs can either promote uniformity or induce aggregation of the bacterial suspensions. Findings have shown significant strain-specific effects of PPAs on bacterial viability and functionality, suggesting that their careful selection can improve bacterial health. Future directions include exploring the molecular mechanisms behind PPAs' effects and their practical applicability in real food systems.

Prevention of Crystal Agglomeration: Mechanisms, Factors, and Impact of Additives

Crystal agglomeration is a common phenomenon for most chemicals and pharmaceuticals. The formation of agglomerates usually lowers product purity and generates a broad particle size distribution. This review focuses on preventing agglomeration in solution crystallization, the storage of crystals, and pharmaceutical preparation processes. The agglomeration mechanisms in these stages are analyzed and the effects of operating parameters are summarized. Furthermore, effective control means related to the crystallization environment are elaborated, including solvents, ultrasound, and additives. Special attention is paid to the influence of additives in preventing the aggregation of both suspensions and dried powders. Besides additives used in solution crystallization, the roles of anti-caking agents, stabilizers of nanosuspensions, and excipients of solid dispersions are also discussed. The additive type and properties like hydrophilicity, hydrophobicity, ionic strength, viscosity, the steric hindrance effect, and intermolecular interactions between additives and crystals can greatly affect the degree of agglomeration.

Characterization of TEMPO-Oxidized Cellulose Nanofiber From Biowaste and Its Influence on Molecular Behavior of Fluorescent Rhodamine B Dye in Aqueous Suspensions

AbstractCellulose nanofiber (CNFs) obtained through TEMPO oxidation was structurally characterized using FT-IR (Fourier Transformed Infrared) and SEM (Scanning Electron Microscopy) spectroscopy. The molecular aggregation and spectroscopic properties of Rhodamine B (Rh-B) in CNFs suspension were investigated using molecular absorption and steady-state fluorescence spectroscopy techniques. The interaction between CNFs particles in the aqueous suspension and the cationic dye compound was examined in comparison to its behavior in deionized water. This interaction led to significant changes in the spectral features of Rh-B, resulting in an increase in the presence of H-dimer and H-aggregate in CNFs suspension. The H-type aggregates of Rh-B in CNFs suspensions were defined by the observation of a blue-shifted absorption band compared to that of the monomer. Even at diluted dye concentrations, the formation of Rh-B’s H-aggregate was observed in CNFs suspension. The pronounced aggregation in suspensions originated from the strong interaction between negatively charged carboxylate ions and the dye. The aggregation behavior was discussed with deconvoluted absorption spectra. Fluorescence spectroscopy studies revealed a significant reduction in the fluorescence intensity of the dye in CNFs suspension due to H-aggregates. Furthermore, the presence of H-aggregates in the suspensions caused a decrease in the quantum yield of Rh-B compared to that in deionized water.

Arsenate and cadmium ions removal from multicomponent solutions of ionic polymers using mesoporous activated biocarbons

Activated biocarbons (AC) obtained in the process of simultaneous pyrolysis and activation of lemon balm (LB) and mint (MT) herbs with H3PO4 were used to purify aqueous solutions of cadmium, arsenate, polyethylenimine (PEI) and poly(acrylic acid) (PAA). The metals show high toxicity in the whole range of their concentrations, whereas the polymers are cytotoxic at high concentrations.The efficiency of As(V) removal from an aqueous solution depends on the pH value, while the Cd(II) adsorption on the activated biocarbons surface is independent on this parameter. The maximum adsorbed amounts are 135.8 mg/g for Cd(II) and 109.6 mg/g for As(V), respectively. The removal of metals ions and polymers from binary systems is lower in comparison to the one-component solutions. This is a consequence of the formation of polymer-metal complexes, that tend to remain in the solution. Additionally, the surface charge density, zeta potential, the size of activated biocarbons aggregates in the aqueous suspensions and the influence of toxic metal ions on the determination of the concentration of polymers in water samples was investigated. The obtained results proved that the PEI concentration can be effectively determined in the presence of metal ions, whereas the procedure of PAA determination requires additional validation.

Revealing roles of S-layer protein (SlpA) in Clostridioides difficile pathogenicity by generating the first slpA gene deletion mutant.

Clostridioides difficile infection (CDI) with high morbidity and high mortality is an urgent threat to public health, and C. difficile pathogenesis studies are eagerly required for CDI therapy. The major surface layer protein, SlpA, was supposed to play a key role in C. difficile pathogenesis; however, a lack of isogenic slpA mutants has greatly hampered analysis of SlpA functions. In this study, the whole slpA gene was successfully deleted for the first time via CRISPR-Cas9 system. Deletion of slpA in C. difficile resulted in smaller, smother-edged colonies, shorter bacterial cell size, and aggregation in suspension. For life cycle, the mutant demonstrated lower growth (changes of optical density at 600 nm, OD600) but higher cell density (colony-forming unit, CFU), decreased toxins production, and inhibited sporulation. Moreover, the mutant was more impaired in motility, more sensitive to vancomycin and Triton X-100-induced autolysis, releasing more lactate dehydrogenase. In addition, SlpA deficiency led to robust biofilm formation but weak adhesion to human host cells.IMPORTANCEClostridioides difficile infection (CDI) has been the most common hospital-acquired infection, with a high rate of antibiotic resistance and recurrence incidences, become a debilitating public health threat. It is urgently needed to study C. difficile pathogenesis for developing efficient strategies as CDI therapy. SlpA was indicated to play a key role in C. difficile pathogenesis. However, analysis of SlpA functions was hampered due to lack of isogenic slpA mutants. Surprisingly, the first slpA deletion C. difficile strain was generated in this study via CRISPR-Cas9, further negating the previous thought about slpA being essential. Results in this study will provide direct proof for roles of SlpA in C. difficile pathogenesis, which will facilitate future investigations for new targets as vaccines, new therapeutic agents, and intervention strategies in combating CDI.

Extreme shifts in pyrite sulfur isotope compositions reveal the path to bonanza gold

Pyrite is the most common sulfide mineral in hydrothermal ore-forming systems. The ubiquity and abundance of pyrite, combined with its ability to record and preserve a history of fluid evolution in crustal environments, make it an ideal mineral for studying the genesis of hydrothermal ore deposits, including those that host critical metals. However, with the exception of boiling, few studies have been able to directly link changes in pyrite chemistry to the processes responsible for bonanza-style gold mineralization. Here, we report the results of high-resolution secondary-ion mass spectrometry and electron microprobe analyses conducted on pyrite from the Brucejack epithermal gold deposit, British Columbia. Our δ34S and trace element results reveal that the Brucejack hydrothermal system experienced abrupt fluctuations in fluid chemistry, which preceded and ultimately coincided with the onset of ultra-high-grade mineralization. We argue that these fluctuations, which include the occurrence of extraordinarily negative δ34S values (e.g., -36.1‰) in zones of auriferous, arsenian pyrite, followed by sharp increases of δ34S values in syn-electrum zones of nonarsenian pyrite, were caused by vigorous, fault valve-induced episodic boiling (flashing) and subsequent inundation of the hydrothermal system by seawater. We conclude that the influx of seawater was the essential step to forming bonanza-grade electrum mineralization by triggering, through the addition of cationic flocculants and cooling, the aggregation of colloidal gold suspensions. Moreover, our study demonstrates the efficacy of employing high-resolution, in situ analytical techniques to map out individual ore-forming events in a hydrothermal system.

Shear thickening of dilute suspensions of fractal silica aggregates

The increase in viscosity under shear known as shear thickening (ST) is an inherent property of a wide variety of dense particulate suspensions. Recent studies indicate that ST systems formed by fractal particles are promising candidates for various practical applications. However, ST in fractal systems remains poorly explored. Here we experimentally study the ST behavior in suspensions of hydrophilic fumed silica (FS) particles in glycerol. Remarkably, unlike non-fractal systems, we observe a strong dependence of the onset stress for ST on the volume fraction of fractal objects and a reversible weakening of the ST response that depends strongly on the particle volume fraction as well as the properties of the FS system. Using in-situ boundary imaging, we map out the spatio-temporal flow properties during ST for different FS systems. We find that the fractal nature and structural properties like the internal branching of the particles can qualitatively explain the complex ST phase diagram of these systems.

Use of turbidimetry for determination of heat treatment intensity applied at pasteurization of milk

Express methods for estimating the intensity of heat treatment of milk are necessary in industry and in research work. For this reason, there are many ways to measure this parameter, which are based on different physical principles, including turbidimetric methods. The Harland & Ashworth turbidimetric method has been developed for a long time, however, due to its high reliability and ease of implementation, it is still used in practice. However, this method has a drawback: it takes a long time to perform the analysis. In this regard, the aim of the work is to develop an express method for evaluating the thermal class of milk based on the principle of measuring the concentration of soluble whey proteins. The result is achieved through the use of a turbidimetric measurement method with optimized sample preparation parameters and parameters for measuring the optical density of a suspension of protein aggregates. The method is implemented as follows. The milk sample is mixed with 0.1 N acetate buffer (pH 4.6) in a ratio that allows to obtain a concentration of soluble milk whey proteins from 0.05% to 0.1%. Recommended dilution coefficients: 1:3 for samples of ultra-pasteurized milk and pasteurized milk with high heat treatment intensity; 1:7 for samples of pasteurized milk with low heat treatment intensity and 1:14 for raw milk samples. The solution is filtered on a membrane filter with a pore size of 0.45 microns. The resulting filtrate is mixed with 24% trichloroacetic acid (TCA) in a 1:1 ratio to coagulate soluble whey proteins and form protein aggregates. After holding for 5–10 minutes, the optical density of the suspension of protein aggregates is measured at a wavelength of 650 nm. The content of water-soluble whey proteins in the sample can be calculated according to the calibration curve. The developed method allows to obtain the measurement result in less time than the Harland & Ashworth turbidimetric method.

The Influence of the Sizes of Nanodiamond Aggregates in Suspensions on the Efficiency of Sorption of 90Y and 177Lu Isotopes for Further Use in Nuclear Medicine

The Influence of the Sizes of Nanodiamond Aggregates in Suspensions on the Efficiency of Sorption of 90Y and 177Lu Isotopes for Further Use in Nuclear Medicine

Identifying the mechanisms behind the stability of silica nano- and micro-particles: Effects of particle size, electrolyte concentration and type of ionic species

Silica nanofluids have emerged as promising agents for various applications, such as water treatment, CO2 absorption, and chemical enhanced oil recovery (CEOR). However, their effectiveness can be hindered when transported through porous media, especially in challenging downhole environments. Aggregation of nanofluid suspensions can damage formation integrity, and brine fluids may unintentionally transport fine micro silica particles, warranting an in-depth examination of micro-particle behavior and stability. This study synthesized silica particles of different sizes (10 nm, 50 nm, 1 μm and 2 μm) and meticulously characterized them using advanced techniques of transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), fourier-transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), thermal gravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) analysis. Subsequently, 560 combinations (in 5 series of 112 experiments) of micro- and nano-fluids in the presence of four different salts (NaCl, CaCl2, MgSO4 and MgCl2) were prepared. The stability and sedimentation of these combinations were investigated based on zeta potential, particle size, pH, electrical conductivity, and UV-spectrophotometry. The results indicated that sodium ions were effective for maintaining suspension stability at lower salt concentrations, while magnesium ions were preferred for higher salinities. Particle size increase led to instability at low salinities but stability at high salinities, where enthalpy dominated over entropy. Derjaguin-Landau-Verwey-Overbeek (DLVO) modeling accurately predicted particle interactions and aggregation tendencies. This investigation enhanced the understanding of the mechanisms governing silica particle stability through diverse analytical methods, addressing their limitations. The analysis of UV data over time revealed insights into sedimentation and aggregation kinetics. In summary, this study comprehensively explored the behavior and stability of silica particles in nano- and micro-fluids, shedding light on their performance in applications ranging from enhanced oil recovery to water treatment.

Holistic Prediction of AuNP Aggregation in Diverse Aqueous Suspensions Based on Machine Vision and Dark-Field Scattering Imaging.

The localized surface-plasmon resonance of the AuNP in aqueous media is extremely sensitive to environmental changes. By measuring the signal of plasmon scattering light, the dark-field microscopic (DFM) imaging technique has been used to monitor the aggregation of AuNPs, which has attracted great attention because of its simplicity, low cost, high sensitivity, and universal applicability. However, it is still challenging to interpret DFM images of AuNP aggregation due to the heterogeneous characteristics of the isolated and discontinuous color distribution. Herein, we introduce machine vision algorithms for the training of DFM images of AuNPs in different saline aqueous media. A visual deep learning framework based on AlexNet is constructed for studying the aggregation patterns of AuNPs in aqueous suspensions, which allows for rapid and accurate identification of the aggregation extent of AuNPs, with a prediction accuracy higher than 0.96. With the aid of machine learning analysis, we further demonstrate the prediction ability of various aggregation phenomena induced by both cation species and the concentration of the external saline solution. Our results suggest the great potential of machine vision frameworks in the accurate recognition of subtle pattern changes in DFM images, which can help researchers build predictive analytics based on DFM imaging data.

Enhancing mesenchymal stem cells cultivated on microcarriers in spinner flasks via impeller design optimization for aggregated suspensions

During the ex vivo expansion of umbilical cord-derived mesenchymal stem cells (hUCMSCs) in a stirred tank bioreactor, the formation of cell–microcarrier aggregates significantly affects cell proliferation and physiological activity, making it difficult to meet the quantity and quality requirements for in vitro research and clinical applications. In this study, computational fluid dynamic (CFD) simulations were used to investigate the effect of an impeller structure in a commercial spinner flask on flow field structure, aggregate formation, and cellular physiological activity. By designing a modified impeller, the aggregate size was reduced, which promoted cell proliferation and stemness maintenance. This study showed that increasing the stirring speed reduced the size of hUCMSC-microcarrier aggregates with the original impeller. However, it also inhibited cell proliferation, decreased activity, and led to spontaneous differentiation. Compared to low stirring speeds, high stirring speeds did not alter the radial flow characteristics and vortex distribution of the flow field, but did generate higher shear rates. The new impeller’s design changed the flow field from radial to axial. The use of the novel impeller with an increased axial pumping rate (Qz) at a similar shear rate compared to the original impeller resulted in a 43.7% reduction in aggregate size, a 37.4% increase in cell density, and a better preservation of the expression of stemness markers (SOX2, OCT4 and NANOG). Increasing the Qz was a key factor in promoting aggregate suspension and size reduction. The results of this study have significant implications for the design of reactors, the optimisation of operating parameters, and the regulation of cellular physiological activity during MSC expansion.Graphical

Chiroptical Generation, Switching, and Long‐Term Memory in Supramolecular Azobenzene‐Pendant Polymer: Regulation by Cellulose Peralkyl Esters, D‐/L‐Glucose Permethyl Esters, Solvents, UV Light Irradiation, and Thermal Annealing Process†

Comprehensive SummaryVarious optically active polymers are known to afford sophisticated chirality‐related functionalities, i.e., asymmetric catalysis, chiroptical switching and memory in UV‐vis‐NIR region, chromatographic separation of enantiomers, and sensors for molecular chirality. Recently, material researchers have paid much attention to the design of chiral supramolecular architectures from achiral polymers upon intermolecular interactions with help of greener biosources. The present article reports an instantaneous generation of ambidextrous supramolecules revealing light‐driven chiroptical switching/memory in UV‐vis region when achiral azobenzene‐containing vinylpolymers are non‐covalently interacted with alkyl ester derivatives of natural cellulose and D‐/L‐glucose. It was recognized that the semi‐synthetic biomaterials efficiently work as chirality‐inducing scaffoldings to several achiral and optically inactive molecules, oligomers, and polymers. Our successful results shed light on a new approach of how inexpensive poly‐/mono‐saccharide derivatives can afford supramolecular chiroptical systems with the azobenzene pendant polymer as aggregates in suspension and liquid‐crystalline films with minimal energy, time, and cost.

Formation and stability of fibers obtained by cold gelation of pea protein isolate aggregates in a hydrodynamic spinning process

Using plant protein sources in the formulation of food products is an important option to reduce the overall carbon footprint of the human diet. However, the ability to convert plant proteins into functional ingredients can hamper their use by the food industry. Our objective was to assemble pea protein isolate (PPI) aggregates into edible fibers. They were obtained by co-injection of a suspension of PPI aggregates with a solution of calcium chloride by means of physico-chemical bonds, i.e. in the absence of thermal treatment or chemical reaction. As soon as specific hydrodynamic conditions were met, homogeneous fibers of few hundreds μm diameter and few cm length were obtained. Small angle X-ray scattering showed that the building blocks of these fibers were dense aggregates of 400 nm radius. Calcium and PPI concentrations required for the processing of fibers were roughly given by the sol-gel state diagram of PPI aggregates. Compared to their dairy protein based equivalent, PPI fibers were obtained with a low mass fraction of protein (3% w/w) and were stable regardless of the concentration of calcium chloride used. We concluded that the robustness of the hydrodynamic spinning process was attributed to the strong reactivity of PPI aggregates with calcium ions and the low tendency of PPI gels to syneresis.

Polymerization of tetrazine-substituted diacetylenes as aggregates in suspension.

Polydiacetylenes (PDAs) are conjugated polymers that have been widely exploited for their chromogenic and fluorogenic transitions upon exposure to external stimuli and biomolecules of interest. Herein, we propose a comparative study of the polymerization dynamics of two diacetylene derivatives, TzDA1 and TzDA2, in the form of aggregates in suspension prepared by reprecipitation method from organic solvents in water, varying the diacetylene concentration and solvent proportions, and sonication in water, varying the time and temperature. Both derivatives bear a tetrazine fluorophore, which serves both to increase the fluorescence quantum yield of the system and to track the polymerization by fluorescence quenching exclusively by the blue-PDA, and differ by the chain termination. It was shown that adding a butyl ester function in TzDA2 to a simple urethane (TzDA1) influences the polymerizability and kinetics of polymerization of the aggregates in suspension. In addition, we showed that also the preparation method and preparation conditions do have an influence on the polymerization dynamics, suggesting that a careful study of these properties should be carried out before investigating the applications of such objects.

Sustainable bioactivity enhancement of ZnO-Ag nanoparticles in antimicrobial, antibiofilm, lung cancer, and photocatalytic applications.

Cancer, microbial infections, and water pollution are significant challenges the modern human population faces. Traditional treatments for cancer and infections often have adverse effects and ecological consequences, while chemical methods for water decontamination can produce harmful byproducts. Metal nanoparticles, particularly zinc oxide (ZnO) and silver (Ag) nanoparticles, show promise in addressing these issues. However, doping Ag on ZnO NPs may synergistically enhance biomedical and therapeutic effects with fewer adverse consequences and improved photocatalytic properties for wastewater treatment. This study aimed to create ZnO and ZnO-Ag nanoparticles through green synthesis and compare their anticancer, antimicrobial, and photocatalytic activity mechanisms. XRD studies determined the crystal diameters of ZnO NPs and ZnO-Ag NPs to be 12.8 nm and 15.7 nm, respectively, with a hexagonal wurtzite structure. The XPS and EDS analyses confirmed the presence of Ag on the ZnO NPs. ZnO NPs and ZnO-Ag NPs exhibited low aggregation in aqueous suspensions, with zeta potentials of -20.5 mV and -22.7 mV, respectively. Evaluating antimicrobial and antibiofilm activity demonstrates that ZnO-Ag NPs have superior potential to ZnO NPs and standard antibiotic drugs against E. coli, S. typhi, B. subtilis, S. aureus, C. albicans, and A. niger. The results of the in vitro cytotoxicity test indicated that on the NCI-H460 lung cancer cell line, ZnO NPs and ZnO-Ag NPs demonstrated IC50 values of 40 μg mL-1 and 30 μg mL-1, respectively. The photocatalytic degradation of methylene blue under direct sunlight revealed that ZnO and ZnO-Ag NPs degraded MB by 98% and 70% in 105 min, respectively. These results show that these nanomaterials may have great potential for treating the aforementioned issues.

Supramolecular temperature responsive assembly of polydopamine reduced graphene oxide.

Graphene oxide (GO) and reduced graphene oxide (rGO) colloidal systems can directly respond to environmental stimuli such as pH, ionic strength, and light by themselves, but not to temperature. Here we show that surface modification of rGO with polydopamine (PDA) leads to a temperature-responsive composite material, even though neither rGO nor PDA have intrinsic temperature responsiveness. Reducing GO with dopamine results in rGO/PDA flakes with hydrophilic PDA clusters attached to hydrophobic rGO domains, which mimics the amphiphilic structure of temperature responsive poly(N-isopropylacrylamide) (PNIPAM). The rGO/PDA flakes self-assemble at temperature higher than 30 °C, causing flake aggregation and precipitation in suspensions with concentration of 0.05 g L-1, which is reversible upon cooling, shaking, and re-heating. A solution-to-gelation transition occurs upon heating suspensions with concentration of 10 g L-1. Nacre-like films and porous monoliths are obtained by drying rGO/PDA suspensions at different concentrations. Films and porous monoliths obtained by drying suspensions that are previously self-assembled through heat have more compact structures compared to those obtained with suspensions that are not heated. Overall, this work introduces the concept of supramolecular temperature responsive assembly of nanomaterials (STRAN), i.e., that temperature response can be introduced in nanomaterials by combining non-responsive components that function cooperatively in supramolecules, whose interactions with solvents can be modulated by temperature changes, mimicking what happens in macromolecular systems such as PNIPAM. STRAN could be applied to nanomaterials beyond GO to develop responsive systems whose self-assembly in suspension and architectural features realized upon drying can be controlled by temperature.

Evaluating the Rheo-electric Performance of Aqueous Suspensions of Oxidized Carbon Black

HypothesisThe macroscopic properties of carbon black suspensions are primarily determined by the agglomerate microstructure built of primary aggregates. Conferring colloidal stability in aqueous carbon black suspensions should thus have a drastic impact on their viscosity and conductivity. ExperimentsCarbon black was treated with strong acids following a wet oxidation procedure. An analysis of the resulting particle surface chemistry and electrophoretic mobility was performed in evaluating colloidal stability. Changes in suspension microstructure due to oxidation were observed using small-angle X-ray scattering. Utilizing rheo-electric measurements, the evolution of the viscosity and conductivity of the carbon black suspensions as a function of shear rate and carbon content was thoroughly studied. FindingsThe carboxyl groups installed on the carbon black surface through oxidation increased the surface charge density and enhanced repulsive interactions. Electrostatic stability inhibited the formation of the large-scale agglomerates in favor of the stable primary aggregates in suspension. While shear thinning, suspension conductivities were found to be weakly dependent on the shear intensity regardless of the carbon content. Most importantly, aqueous carbon black suspensions formulated from electrostatically repulsive primary aggregates displayed a smaller rise in conductivity with carbon content compared to those formulated from attractive agglomerates.

English translation of Giesekus's famous article on the elasticity of liquids

Starting from a suspension of elastic dumbbells or chain-like particle aggregates as a simple model of a viscoelastic liquid, the rheological equation of state is inductively derived into which the concept of an “elastic strain component” (recoverable strain) is incorporated and can be understood as a nonlinear extension of the so-called “generalized Maxwell model.” Here, the liquid is characterized by a sequence of nested continua, each associated with an elasticity law. The consideration of the directional dependence of the mobility of the structural elements requires that the behavior of the liquids represented in this way generally deviates from a Weissenberg liquid.